Evaluation of Pepper Spray.
Series: NIJ Research in Brief
Published: February 1997
15 pages
31,083 bytes
U.S. Department of Justice
Office of Justice Programs
National Institute of Justice
National Institute of Justice
Research in Brief
Jeremy Travis, Director
February 1997
Evaluation of Pepper Spray
by Steven M. Edwards, John Granfield, and Jamie
Onnen
------------------------------
Figures, charts, forms, and tables are not included
in this ASCII plain-text file. To view this
document in its entirety, download the Adobe
Acrobat graphic file available from this Web site
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------------------------------
Issues and Findings
Discussed in the Brief: The implementation process
and field test results of a project to evaluate the
effectiveness of pepper spray in police
confrontations with humans and animals. A research
team from the International Association of Chiefs
of Police analyzed Baltimore County Police
Department policies, implementation training, and
use of pepper spray from July 1993 to March 1994.
Key Issues:
o Whether OC spray can effectively incapacitate
humans -- including those who are intoxicated,
drugged, or mentally disturbed -- in confrontations
with police.
o Whether OC spray can reduce the number of
assaults against police attempting to subdue or
arrest hostile/aggressive subjects.
o Whether OC use helps to reduce injuries to both
officers and suspects in encounters between the
two.
o Whether police use-of-force or brutality
complaints are lodged less frequently due to use of
OC.
o Whether OC is effective in neutralizing attacking
or threatening dogs.
Key Findings:
o OC spray successfully incapacitated humans in 156
out of 174 (90 percent) confrontations.
o In 18 encounters, subjects were not fully
"subdued " by OC; in 7 of these incidents, subjects
exhibited bizarre behavior and appeared to be on
drugs or mentally troubled, thus suggesting that
such individuals may not yield to OC's effects.
o While assaults on officers were declining prior
to implementation of the OC spray program, the rate
of decline increased after OC was introduced.
o Twenty-one officers received minor injuries when
they used the spray, but none reported lost work
days.
o Similarly, only 14 suspects received injuries,
none of which required hospital treatment.
o Use-of-force complaints decreased by 53 percent
in the study period despite decreased manpower and
increased demand for services. No complaints
addressed the use of OC.
o Although training instructions stated that sprays
were maximally effective from a distance of 4 to 6
feet, many officers applied the aerosol to humans
from distances of less than 3 feet, which may have
diminished the spray's effectiveness.
o Overall, study findings showed that a
well-developed OC-spray program can provide
operational benefits to police.
Target audience: Law enforcement officials and
trainers; State, local, and Federal policymakers;
researchers.
------------------------------
Violent encounters between police officers and
individuals resisting arrest have historically
resulted in injury and frequently in complaints
about the level of force used by police. In
addition to concern over these issues, increased
civil liability and court-imposed limitations on
the use of deadly force have stimulated the search
for safe and effective less-than-lethal (LTL) force
alternatives. One widely used option is oleoresin
capsicum (OC) aerosol, commonly called pepper
spray.
Despite extensive applications in hundreds of
police departments, few systematic studies of OC
usage and effectiveness have been documented. A
National Institute of Justice-sponsored assessment
of pepper spray's usefulness focused on the
Baltimore County Police Department's (BCoPD's)
operations from July 1993 through March 1994.
A research team from the International Association
of Chiefs of Police (IACP) analyzed the BCoPD data
and found that the use of OC in arrest and other
confrontational encounters effectively neutralized
aggressive suspects and animals. Study findings
also suggest that the use of OC reduced the
incidence of assaults on police officers, injuries
to both officers and suspects, and use-of-force or
brutality complaints registered against BCoPD.
This Research in Brief compares OC spray to other
chemicals used in law enforcement and discusses the
BCoPD study in terms of methodology, implementation
issues, and assessment results.
Chemical weapon use in law enforcement
For centuries, various forms of chemical agents
have been used in war as offensive weapons. As
early as 2300 B.C., Chinese armies dispersed enemy
forces by using "stink pots" -- red pepper burned
in hot oil that produced irritating and suffocating
smoke -- in massive frontal assaults. After World
War I, however, an interest in extending the use of
chemicals into the realm of law enforcement
emerged. It was hypothesized that these agents
could control criminals and riotous crowds as
effectively as they controlled enemies during
warfare. The three chemicals -- chloroacetophenone,
o-chlorobenzylidene malononitrile, and oleoresin
capsicum -- that have been used in law enforcement
have shown major practical differences.
o Chloroacetophenone (CN). CN is a powerful
lacrimator and respiratory irritant. Exposure to CN
causes copious, uncontrollable tearing; difficult,
shallow breathing; chest tightness; stinging
sensations on the skin; and nausea. Psychological
effects of fear and panic may also occur. As an
irritant that relies on pain compliance, CN is most
effective on those individuals who are lucid and
have a normal pain threshold. Individuals who are
intoxicated, extremely agitated, or mentally ill
generally are less affected by the agent because of
their greater tolerance for pain.
Although humans are susceptible to the agent's
effects, animals suffer little, if at all, from the
symptoms induced by CN. In addition, CN
effectiveness is temperature-dependent. While the
agent is useful in any temperature over 50 degrees
F, it
is most effective when used in temperatures of 72
degrees
F and higher.
CN use also creates decontamination problems since
the microscopic particles can remain airborne for
some time after being dispersed. Dissipation time
depends on the amount of the agent released, air
current activity, temperature, and humidity.
Finally, CN cross-contamination between subjects
and police officers is common. Officers note that
they are often contaminated by the agent when
arresting and transporting sprayed subjects. This
cross-contamination is thought to be responsible
for officers' reluctance to use CN.
o o-Chlorobenzylidene malononitrile (CS). CN was
replaced as a riot control agent by the U.S. Army
and the National Guard around 1960. Officials
believed that the replacement, CS, sometimes called
super tear gas, was considerably less toxic and
delivered more immediate effects than CN. Following
military protocols, American law enforcement
agencies subsequently adopted CS in 1965. Like CN,
it is classified as a solid, not a gas, since it
requires a carrying agent to disperse it into the
desired target area. CS, a lacrimating irritant,
immediately affects the mucous membranes, producing
tears, runny nose, and persistent coughing or
sneezing. Additional symptoms of exposure include
respiratory distress accompanied by tightness in
the chest, a burning sensation on the skin, and
nausea or vomiting. In addition to physical
effects, CS can also cause intense fear, panic, and
cognitive disorientation.
Like CN, CS is more effective on those areas of the
skin that are moist and is virtually ineffective on
animals. Unlike CN, CS is considered to be
effective over a wide temperature range. The
microparticulate nature of CS results in agent
persistency and thus can make decontamination
problematic, especially in enclosed or confined
spaces.
Serious injury to an individual is improbable if CS
is used properly. Extensive toxicological testing
indicates that, in spite of the potency of CS, it
is safer, less toxic, and more effective than CN.
o Oleoresin capsicum (OC). OC, a naturally
occurring substance derived from the cayenne pepper
plant, is classified as an inflammatory agent. On
contact with OC, the mucous membranes of the eyes,
nose, and throat immediately become inflamed and
swollen. The symptomatic swelling produces
involuntary eye closure due to dilating
capillaries; nasal and sinus drainage; constricted
airway; and temporary paralysis of the larynx,
causing gagging, coughing, and shortness of breath.
The extract of peppers causes the blood vessels to
dilate and the blood to rush to the upper body; the
skin appears inflamed, resembling a burn.
OC's inflammatory properties purportedly render the
agent more effective than CN and CS on violent,
intoxicated, drugged, and mentally ill individuals.
Moreover, the symptomatic eye closure and
constriction of the respiratory tract explain why
OC is so effective on animals. No special
decontamination protocols are required for OC
because it is biodegradable. Unlike CN and CS
irritants, OC will not persist on clothing or
affected areas.
Examination of a national sample of in-custody
deaths that occurred subsequent to OC use has
excluded the agent as a contributory factor. This
analysis concluded that, to date, OC has not caused
any deaths.[1] Finally, OC use does not result in
dermatitis, skin depigmentation, or burns.
CN and CS are still used by many law enforcement
agencies, especially for tactical use in
crowd-control situations. Primarily because of the
potential risk of injury and cross-contamination,
as well as decontamination problems associated with
their use, law enforcement officials began to use
OC as a less harmful, more dependable alternative.
Although available since the mid-1970s, OC was not
widely used until recently.
Study method
Research staff adopted a two-pronged approach to
the OC spray evaluation task, which they initiated
in mid-July 1993. The first phase involved
examination of OC adoption and implementation
issues. The second stage was concerned with
assessing the impact of OC spray in confrontations
between police officers and citizens, as well as
police officers and dogs.
Phase 1. Officers and command staff members who
initiated and were critically involved with the
project met throughout the study period to address
specific OC-related issues. Research staff attended
these meetings and collected information on the
process of OC adoption and implementation. Issues
included selection of the pepper spray product,
development of a written policy on its use,
development of a training program and materials,
implementation of documentation for reporting
pepper spray usage, and identification of followup
training needs.
Phase 2. Project data were provided by BCoPD's
Crime Analysis Unit and Internal Affairs Section,
as well as by the monthly Maryland Law Enforcement
Officers Killed or Assaulted data sheets. This
information was supported by data collected from an
instrument developed by the research staff to track
each spraying incident.
Every officer discharging OC spray in a
confrontational encounter was required to complete
the OC spray data collection form, which contained
both open-ended and specified-choice questions
relating to prevailing weather conditions,
suspect's behavior, OC application area, injury (if
any) received, and decontamination. The OC data
form was completed along with a departmental
incident report as soon as practical after
conclusion of the encounter. A second data
collection instrument, an unstructured followup
interview, was developed to validate information
collected by the OC data form. These unstructured
officer interviews were conducted by the onsite
observer to allow for the addition of any comments,
suggestions, or officer observations regarding the
specific encounter and the effectiveness of the
spray.
Prior to their use in BCoPD, the OC data collection
sheet and unstructured follow-up interview format
were pretested in the Anne Arundel County,
Maryland, Police Department. Results indicated that
measurement instruments were both suitable and
easily completed.
Findings: adoption and implementation
Selection of product. The Baltimore County Police
Department had previously undertaken a thorough
study of the OC product that it wanted to provide
its officers. BCoPD selected a product containing a
5-percent concentration of OC delivered through a
fogger system, which does not require precision
aiming.
BCoPD training. The Baltimore County Police
Department has sole responsibility for delivery of
police services to approximately 695,000 people who
reside in urban, suburban, and rural settings
within its 612 square-mile jurisdiction. Eighty
percent of the department's officers are assigned
to the Field Operations Bureau, and they responded
to 442,436 calls for service in 1993, which
included 44,074 Part I offenses. The department
needed to train approximately 1,400 officers in a
3-hour block of instruction -- without disrupting
assignments, affecting manpower, or incurring
payment of overtime. To minimize disruption, OC
training was incorporated into officer inservice
firearms training, which began on July 12, 1993,
and continued through December 31, 1993. During
this time, 1,345 officers were trained in the use
of OC spray and issued canisters.
Standard operating procedures. The BCoPD committee
charged with examining the feasibility of OC
adoption drafted a Standard Operating Procedure
(SOP), following consultation with BCoPD's legal
counsel, training officers, Internal Affairs, and
command and staff officers. Additional directives
were added following the completion of instructor
training and writing of the lesson plan. The SOP
requires all members of BCoPD whose normal duties
include making arrests or supervising arrest
situations to carry OC spray. Uniformed members of
the department are to carry the device on their gun
belts in an issued holster, while nonuniformed
officers are to carry pen-sized containers after
completing a training program and demonstrating
their competence in handling and using the OC
spray.
Guidelines for usage. BCoPD, like most other police
departments, adheres to the use-of-force continuum
and its range of response, beginning with the mere
presence of an officer and escalating to the use of
deadly force. According to BCoPD procedures, OC
spray may be used by an officer in any arrest
situation when:
o The aggressor has failed to comply with the
officer's verbal instructions.
o The aggressor has been advised of OC's impending
use.
o The officer is about to use hands-on tactics to
defend himself against active hostile resistance.
o The officer is confronted by an aggressive
animal.
BCoPD thus places the use of OC spray above verbal
commands on the force continuum as a means of
control and restraint. BCoPD emphasizes that OC is
not a substitute for a firearm. If, when faced by
an armed individual, the officer deems deadly force
necessary, then BCoPD considers the firearm to be
the weapon of choice.
During the study, patrol officers voiced concern
about whether they would be allowed to use deadly
force if attacked with OC spray. The Legal Officers
Section of the IACP holds that an officer may use
deadly force to protect himself from the use or
threatened use of OC spray when reasonably sure
that deadly force will be used against him if he
becomes incapacitated. Incapacitation includes
situations in which officers may be unable to
adequately defend themselves due to the effect of
chemical sprays. Criteria for determining when to
use deadly force incorporated situations in which
OC was used against police (see "Reasonable Use of
Deadly Force").
The Baltimore County Police Department operating
procedures also outlined how to use the product and
decontaminate the prisoner after use. The SOP
directs officers to assure the suspect of the
temporary nature of OC's effects and to provide air
and water as first aid. BCoPD officers were
instructed to remove the sprayed subject from the
spray area into fresh air and to allow access to
"copious amounts" of water, as soon as possible.
Since BCoPD patrol vehicles did not carry water or
any special equipment to aid in the decontamination
process, they relied on physically removing
suspects, instructing sprayed persons not to rub
their eyes, and transporting them quickly to a
source of water.
Use of pepper spray
During the study period, Baltimore County officers
used OC in response to 194 (174 human and 20
animal) incidents, which fell into various
categories of complaints that beat police officers
often handle. These types of complaints usually
involved aggressive, excitable behavior on the part
of both the complainant and victim. Moreover, they
tended to escalate quickly, resulting in
confrontational outcomes.
Thirty-nine percent of the incidents occurred
inside some structure (e.g., house, car), while the
remaining incidents occurred "out-of-doors."
Weather conditions did not seem to influence either
an officer's decision to use OC or the spray's
effect on suspects. Eighty-four percent of the
human subjects sprayed were male and 16 percent
were female. Generally, sprayed individuals were
intoxicated (drugs or alcohol), belligerent, and/or
combative. The majority (89 percent) of incidents
involved suspects who physically threatened the
police officer; very few incidents involved the use
of firearms or knives. The arrest/intervention
incidents necessitating the use of the spray were
primarily battery, assault, and disorderly conduct
(see exhibits 1 and 2).
Effectiveness of OC use
Overall, OC was very effective in the 194 incidents
where it was used (see "Officers' Comments on OC"
on page 6). A total of 156 (90 percent) of the 174
individuals sprayed were incapacitated enough to be
effectively arrested. Data indicate that almost all
officers applied OC to the suspect's face, as they
had been directed in training. However, officers
generally did not spray from a distance of 4 to 6
feet as instructed. In 144 incidents, the spray was
activated at a distance of 3 feet or less; in 102
of these, OC was sprayed at a distance of 2 feet or
less. As a result, OC may not have been maximally
effective.
Yet the data show that OC worked even if it was not
sprayed from the distance suggested by the
manufacturer. In 144 incidents, only one spray was
required to incapacitate a subject; officers used
the full contents of an issued container of OC to
control suspects in four separate incidents. No
data indicated that spraying more than one short
burst produced better effects, if the subject were
given a "good" spray the first time. The data
showed that 117 individuals (67 percent) were
classified by officers as submissive after the OC
had been applied; 27 individuals (16 percent) were
listed as complying with officer instructions after
being sprayed (see exhibit 3). The difference
between the terms "submissive" and "compliant" is
subtle,[2] and it might be more appropriate to
collapse the two categories into one. When the
categories are collapsed, 144 (83 percent) of the
174 subjects were sufficiently neutralized to yield
to officer orders. Thirty individuals (17 percent)
struggled or otherwise failed to follow officer
instructions.
Eighteen of these 30 struggling subjects were
classified by officers as not fully incapacitated
by the OC spray. According to officer reports, the
OC had no effect on seven suspects. These seven
individuals exhibited drugged behavior or seemed to
have emotional problems. These data indicate that
individuals who are heavily intoxicated, drugged,
or mentally unstable may be resistant or immune to
OC's effects or that OC may actually exacerbate the
difficulty associated with controlling such
persons.[3] Additionally, these types of encounters
may cause the officer to be cross-contaminated if
the incident escalates to a physical confrontation.
BCoPD's experience indicates that training officers
may want to stress the importance of accurately
assessing the likely impact of pepper spray in such
an encounter and of being prepared to select
another control alternative.
Animal control. Interest in OC's effectiveness in
animal encounters was high because, prior to
project implementation, BCoPD had experienced a
number of incidents where officers were forced to
shoot threatening or attacking dogs. During the OC
field study, dogs were sprayed with OC in 20
incidents where the animals posed a danger to
officers. Ten of the dogs sprayed weighed between
25 and 50 pounds, and 6 weighed more than 50
pounds.
Data showed that officers sprayed the dogs at
distances greater than those from which they
sprayed humans. The majority of dogs were sprayed
from a distance of 3 to 8 feet, whereas most humans
were sprayed from a distance of 1 to 3 feet. The
difference in application distances may account for
the differences in the effectiveness levels for
dogs and humans. OC was effective nearly 100
percent of the time in dog encounters (one officer
was bitten but required no medical treatment).
Other results of OC use
Assaults on officers. Three years of prior assault
data (pre-OC data) were collected for comparison
with data from the period after which OC was
adopted by the department (post-OC data). The
pre-OC data were examined to identify any possible
trends regarding assaults. Overall, these data
showed that officer assaults were decreasing prior
to OC use. The post-OC data indicated that assaults
continued to decline. In fact, the total number of
officers assaulted in the post-OC period was
substantially lower than in any pre-OC data period.
While it is likely that the introduction of OC
spray contributed to this significant decline, the
finding must be considered preliminary, since the
pre- and post-data for this study were not strictly
comparable in all cases.
Injuries to officers. Data from the spray
collection form showed that few officers were
injured when they used OC to control a
confrontational encounter. Only 21 officers (11
percent) reported receiving any injury (see exhibit
4). Most of these were minor and resulted in no
lost work time. Although data from the pre-OC use
period were not comparable and did not permit a
complete before-and-after analysis, the relatively
low level of injuries sustained by officers in the
post-OC period suggests that OC use has the
potential to reduce officer injuries in
confrontational situations.
Injuries to suspects. Very few suspect injuries
occurred during the post-OC project period. Of the
174 spray incidents, only 14 suspects (8 percent)
received any injuries, and all of these were minor,
requiring no hospital treatment (see exhibit 4).
Staff were not able to gather pre-OC comparison
data; however, it was hypothesized that if suspects
were injured, complaints of force would be filed
more often. The data collected during the study
period indicated that such complaints were
decreasing at a rate greater than that observed
prior to the introduction of OC. It is reasonable
to conclude that OC had a positive effect on
reducing the number of suspect injuries.
Use-of-force complaints. Departmental policy states
that a use-of-force report must be completed if the
subject complains of injury as a result of arrest
and goes to the hospital for medical treatment.
However, as is true for other less-than-lethal
weapons, a use-of-force report is not required for
OC, absent a complaint or hospital treatment. BCoPD
officials concluded that treating OC differently
could inappropriately hinder its use.
Data suggest that despite an increase in calls for
service and fewer patrol officers working their
beats, use-of-force complaints declined by 53
percent during the second pre-OC period (July 1991
through March 1992 ) and the post-OC period.
Similarly, a reduction of 40 percent occurred
between the third pre-OC period (July 1992 through
March 1993) and the post-OC period (see exhibit 5).
Since no other major policy changes regarding use
of force took place during pre- and post-data
collection, it is likely that the use of pepper
spray accounted for the decrease in complaints.
Interviews with Internal Affairs officers add
weight to this finding. These officers noted that,
unlike those of impact weapons, the effects of OC
are short-lived and nontraumatic; pepper spray thus
reduces the likelihood that brutality or excessive
force complaints would be lodged. In addition,
sprayed individuals received aftercare from the
officers who sprayed them, which may have obviated
the need to complain.
During the time of data collection (July 1993
through March 1994) and over the span of 174
sprayings, five complaints of brutality and one
use-of-force case were received by BCoPD. These
complaints centered on the officer's purportedly
inappropriate behavior and did not address the
spray itself. To date, BCoPD has not had any
complaints or suits filed that relate to the issue
of OC spray.
Summary
Most police departments in the United States are
concerned about officer and suspect safety. In
recent years, this concern has focused on injuries
to police officers and citizens during arrest
confrontations. To meet this problem, departments
have sought answers in technology involving
less-than-lethal weapons. Aerosol pepper spray is
one weapon from the LTL arsenal that effectively
addresses the issue of officer/citizen injury.
This study's findings indicate that BCoPD
successfully implemented its OC operation.
Statistical measurements of effectiveness were
high, and those related to officer assaults,
officer and citizen injuries, and use-of-force
complaints were low. Study findings showed that OC
spray offers advantages over more problematic
sprays and that a well-developed OC spray program
can provide a variety of operational benefits for
law enforcement agencies. In addition, the process
followed by BCoPD could guide other police
departments interested in OC implementation.
Notes
1. Granfield, John, Jamie Onnen, and Charles S.
Petty, M.D., Pepper Spray and In-Custody Deaths,
Executive Brief, Alexandria, Virginia:
International Association of Chiefs of Police,
March 1994.
2. The terms "submissive" and "compliant" were used
by officers completing the data collection form. An
individual officer's understanding and expectation
of OC's effect on a suspect may cause him or her to
make a distinction between the terms. Officers who
believe that the purpose of OC is to totally
incapacitate a subject, with no resistance, might
describe the suspect as submissive and conclude,
therefore, that the product worked. If the OC did
not perform as expected, the same officer might
report that the product had no effect -- despite
the fact that the suspect was easier to arrest as a
result of being sprayed. Other officers might
believe that the product worked well, even though
the suspect offered a struggle. This discussion is
offered to caution against strict interpretation of
subjective responses.
3. More research is required to obtain definitive
answers to the question of how intoxication, drug
use, and/or mental illness affect a person's
reaction to OC spray.
------------------------------
Reasonable Use of Deadly Force When Officers Are
Attacked With OC
When a criminal attacks an officer with OC spray,
he does so with the intent to harm the officer,
escape, or both. It is common knowledge that a high
percentage of officers who are incapacitated or
have had their guns taken away are later shot with
their own weapons. To ask an officer to take a
chance that the OC spray attacker is going to walk
away after incapacitating the officer would be, in
the opinion of IACP's Legal Officers Section,
unconscionable.
In determining whether an officer's use of deadly
force was reasonable, the following factors may be
considered:
o The nature of the crime committed by the person
or persons confronting the officer.
o The nature of the verbal or physical threats
posed by the person confronting the officer.
o The relative strength and fighting skills of the
officer and his opponent.
o The number of officers versus the number of
potential assailants.
o The nature of weapons in the possession of or
available to the assailant.
o The ability to circumvent the potential effects
of OC spray.
o The alternative means of defending against the
use/effects of OC spray.
o The availability of assistance from other nearby
officers.
---------------------------
Officers' Comments on OC
The following comments were extracted from the OC
data collection sheets completed by the BCoPD
officers or from followup interviews:
o Wish we had had it a while ago.
o I think it's a great...alternative to initial use
of force.
o Definitely better than using a nightstick.
o The word is out (on the street)...all people have
to do is hear the Velcro (copyright) and they
comply pretty quickly. [The officer who made this
comment had actually pulled the OC from his holster
at least 10 times, but had sprayed it only once.]
o Some subjects actually apologize after being
sprayed.
------------------------------
Findings and conclusions of the research reported
here are those of the authors and do not
necessarily reflect the official position or
policies of the U.S. Department of Justice.
The National Institute of Justice is a component of
the Office of Justice Programs, which also includes
the Bureau of Justice Assistance, Bureau of Justice
Statistics, Office of Juvenile Justice and
Delinquency Prevention, and the Office for Victims
of Crime.
------------------------------
NCJ 162358
The full report summarized in this Research in
Brief was prepared by Steven M. Edwards, John
Granfield, and Jamie Onnen under National Institute
of Justice grant number 92-IJ-CX-K026. The authors
were with the International Association of Chiefs
of Police while conducting their evaluation.
Questions about the full report may be directed to
John Firman, research coordinator, IACP.
------------------------------
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Evaluation of Pepper Spray.
Series: NIJ Research in Brief
Published: February 1997
15 pages
31,083 bytes
U.S. Department of Justice
Office of Justice Programs
National Institute of Justice
National Institute of Justice
Research in Brief
Jeremy Travis, Director
February 1997
Evaluation of Pepper Spray
by Steven M. Edwards, John Granfield, and Jamie
Onnen
------------------------------
Figures, charts, forms, and tables are not included
in this ASCII plain-text file. To view this
document in its entirety, download the Adobe
Acrobat graphic file available from this Web site
or order a print copy from NCJRS at 800-851-3420.
------------------------------
Issues and Findings
Discussed in the Brief: The implementation process
and field test results of a project to evaluate the
effectiveness of pepper spray in police
confrontations with humans and animals. A research
team from the International Association of Chiefs
of Police analyzed Baltimore County Police
Department policies, implementation training, and
use of pepper spray from July 1993 to March 1994.
Key Issues:
o Whether OC spray can effectively incapacitate
humans -- including those who are intoxicated,
drugged, or mentally disturbed -- in confrontations
with police.
o Whether OC spray can reduce the number of
assaults against police attempting to subdue or
arrest hostile/aggressive subjects.
o Whether OC use helps to reduce injuries to both
officers and suspects in encounters between the
two.
o Whether police use-of-force or brutality
complaints are lodged less frequently due to use of
OC.
o Whether OC is effective in neutralizing attacking
or threatening dogs.
Key Findings:
o OC spray successfully incapacitated humans in 156
out of 174 (90 percent) confrontations.
o In 18 encounters, subjects were not fully
"subdued " by OC; in 7 of these incidents, subjects
exhibited bizarre behavior and appeared to be on
drugs or mentally troubled, thus suggesting that
such individuals may not yield to OC's effects.
o While assaults on officers were declining prior
to implementation of the OC spray program, the rate
of decline increased after OC was introduced.
o Twenty-one officers received minor injuries when
they used the spray, but none reported lost work
days.
o Similarly, only 14 suspects received injuries,
none of which required hospital treatment.
o Use-of-force complaints decreased by 53 percent
in the study period despite decreased manpower and
increased demand for services. No complaints
addressed the use of OC.
o Although training instructions stated that sprays
were maximally effective from a distance of 4 to 6
feet, many officers applied the aerosol to humans
from distances of less than 3 feet, which may have
diminished the spray's effectiveness.
o Overall, study findings showed that a
well-developed OC-spray program can provide
operational benefits to police.
Target audience: Law enforcement officials and
trainers; State, local, and Federal policymakers;
researchers.
------------------------------
Violent encounters between police officers and
individuals resisting arrest have historically
resulted in injury and frequently in complaints
about the level of force used by police. In
addition to concern over these issues, increased
civil liability and court-imposed limitations on
the use of deadly force have stimulated the search
for safe and effective less-than-lethal (LTL) force
alternatives. One widely used option is oleoresin
capsicum (OC) aerosol, commonly called pepper
spray.
Despite extensive applications in hundreds of
police departments, few systematic studies of OC
usage and effectiveness have been documented. A
National Institute of Justice-sponsored assessment
of pepper spray's usefulness focused on the
Baltimore County Police Department's (BCoPD's)
operations from July 1993 through March 1994.
A research team from the International Association
of Chiefs of Police (IACP) analyzed the BCoPD data
and found that the use of OC in arrest and other
confrontational encounters effectively neutralized
aggressive suspects and animals. Study findings
also suggest that the use of OC reduced the
incidence of assaults on police officers, injuries
to both officers and suspects, and use-of-force or
brutality complaints registered against BCoPD.
This Research in Brief compares OC spray to other
chemicals used in law enforcement and discusses the
BCoPD study in terms of methodology, implementation
issues, and assessment results.
Chemical weapon use in law enforcement
For centuries, various forms of chemical agents
have been used in war as offensive weapons. As
early as 2300 B.C., Chinese armies dispersed enemy
forces by using "stink pots" -- red pepper burned
in hot oil that produced irritating and suffocating
smoke -- in massive frontal assaults. After World
War I, however, an interest in extending the use of
chemicals into the realm of law enforcement
emerged. It was hypothesized that these agents
could control criminals and riotous crowds as
effectively as they controlled enemies during
warfare. The three chemicals -- chloroacetophenone,
o-chlorobenzylidene malononitrile, and oleoresin
capsicum -- that have been used in law enforcement
have shown major practical differences.
o Chloroacetophenone (CN). CN is a powerful
lacrimator and respiratory irritant. Exposure to CN
causes copious, uncontrollable tearing; difficult,
shallow breathing; chest tightness; stinging
sensations on the skin; and nausea. Psychological
effects of fear and panic may also occur. As an
irritant that relies on pain compliance, CN is most
effective on those individuals who are lucid and
have a normal pain threshold. Individuals who are
intoxicated, extremely agitated, or mentally ill
generally are less affected by the agent because of
their greater tolerance for pain.
Although humans are susceptible to the agent's
effects, animals suffer little, if at all, from the
symptoms induced by CN. In addition, CN
effectiveness is temperature-dependent. While the
agent is useful in any temperature over 50 degrees
F, it
is most effective when used in temperatures of 72
degrees
F and higher.
CN use also creates decontamination problems since
the microscopic particles can remain airborne for
some time after being dispersed. Dissipation time
depends on the amount of the agent released, air
current activity, temperature, and humidity.
Finally, CN cross-contamination between subjects
and police officers is common. Officers note that
they are often contaminated by the agent when
arresting and transporting sprayed subjects. This
cross-contamination is thought to be responsible
for officers' reluctance to use CN.
o o-Chlorobenzylidene malononitrile (CS). CN was
replaced as a riot control agent by the U.S. Army
and the National Guard around 1960. Officials
believed that the replacement, CS, sometimes called
super tear gas, was considerably less toxic and
delivered more immediate effects than CN. Following
military protocols, American law enforcement
agencies subsequently adopted CS in 1965. Like CN,
it is classified as a solid, not a gas, since it
requires a carrying agent to disperse it into the
desired target area. CS, a lacrimating irritant,
immediately affects the mucous membranes, producing
tears, runny nose, and persistent coughing or
sneezing. Additional symptoms of exposure include
respiratory distress accompanied by tightness in
the chest, a burning sensation on the skin, and
nausea or vomiting. In addition to physical
effects, CS can also cause intense fear, panic, and
cognitive disorientation.
Like CN, CS is more effective on those areas of the
skin that are moist and is virtually ineffective on
animals. Unlike CN, CS is considered to be
effective over a wide temperature range. The
microparticulate nature of CS results in agent
persistency and thus can make decontamination
problematic, especially in enclosed or confined
spaces.
Serious injury to an individual is improbable if CS
is used properly. Extensive toxicological testing
indicates that, in spite of the potency of CS, it
is safer, less toxic, and more effective than CN.
o Oleoresin capsicum (OC). OC, a naturally
occurring substance derived from the cayenne pepper
plant, is classified as an inflammatory agent. On
contact with OC, the mucous membranes of the eyes,
nose, and throat immediately become inflamed and
swollen. The symptomatic swelling produces
involuntary eye closure due to dilating
capillaries; nasal and sinus drainage; constricted
airway; and temporary paralysis of the larynx,
causing gagging, coughing, and shortness of breath.
The extract of peppers causes the blood vessels to
dilate and the blood to rush to the upper body; the
skin appears inflamed, resembling a burn.
OC's inflammatory properties purportedly render the
agent more effective than CN and CS on violent,
intoxicated, drugged, and mentally ill individuals.
Moreover, the symptomatic eye closure and
constriction of the respiratory tract explain why
OC is so effective on animals. No special
decontamination protocols are required for OC
because it is biodegradable. Unlike CN and CS
irritants, OC will not persist on clothing or
affected areas.
Examination of a national sample of in-custody
deaths that occurred subsequent to OC use has
excluded the agent as a contributory factor. This
analysis concluded that, to date, OC has not caused
any deaths.[1] Finally, OC use does not result in
dermatitis, skin depigmentation, or burns.
CN and CS are still used by many law enforcement
agencies, especially for tactical use in
crowd-control situations. Primarily because of the
potential risk of injury and cross-contamination,
as well as decontamination problems associated with
their use, law enforcement officials began to use
OC as a less harmful, more dependable alternative.
Although available since the mid-1970s, OC was not
widely used until recently.
Study method
Research staff adopted a two-pronged approach to
the OC spray evaluation task, which they initiated
in mid-July 1993. The first phase involved
examination of OC adoption and implementation
issues. The second stage was concerned with
assessing the impact of OC spray in confrontations
between police officers and citizens, as well as
police officers and dogs.
Phase 1. Officers and command staff members who
initiated and were critically involved with the
project met throughout the study period to address
specific OC-related issues. Research staff attended
these meetings and collected information on the
process of OC adoption and implementation. Issues
included selection of the pepper spray product,
development of a written policy on its use,
development of a training program and materials,
implementation of documentation for reporting
pepper spray usage, and identification of followup
training needs.
Phase 2. Project data were provided by BCoPD's
Crime Analysis Unit and Internal Affairs Section,
as well as by the monthly Maryland Law Enforcement
Officers Killed or Assaulted data sheets. This
information was supported by data collected from an
instrument developed by the research staff to track
each spraying incident.
Every officer discharging OC spray in a
confrontational encounter was required to complete
the OC spray data collection form, which contained
both open-ended and specified-choice questions
relating to prevailing weather conditions,
suspect's behavior, OC application area, injury (if
any) received, and decontamination. The OC data
form was completed along with a departmental
incident report as soon as practical after
conclusion of the encounter. A second data
collection instrument, an unstructured followup
interview, was developed to validate information
collected by the OC data form. These unstructured
officer interviews were conducted by the onsite
observer to allow for the addition of any comments,
suggestions, or officer observations regarding the
specific encounter and the effectiveness of the
spray.
Prior to their use in BCoPD, the OC data collection
sheet and unstructured follow-up interview format
were pretested in the Anne Arundel County,
Maryland, Police Department. Results indicated that
measurement instruments were both suitable and
easily completed.
Findings: adoption and implementation
Selection of product. The Baltimore County Police
Department had previously undertaken a thorough
study of the OC product that it wanted to provide
its officers. BCoPD selected a product containing a
5-percent concentration of OC delivered through a
fogger system, which does not require precision
aiming.
BCoPD training. The Baltimore County Police
Department has sole responsibility for delivery of
police services to approximately 695,000 people who
reside in urban, suburban, and rural settings
within its 612 square-mile jurisdiction. Eighty
percent of the department's officers are assigned
to the Field Operations Bureau, and they responded
to 442,436 calls for service in 1993, which
included 44,074 Part I offenses. The department
needed to train approximately 1,400 officers in a
3-hour block of instruction -- without disrupting
assignments, affecting manpower, or incurring
payment of overtime. To minimize disruption, OC
training was incorporated into officer inservice
firearms training, which began on July 12, 1993,
and continued through December 31, 1993. During
this time, 1,345 officers were trained in the use
of OC spray and issued canisters.
Standard operating procedures. The BCoPD committee
charged with examining the feasibility of OC
adoption drafted a Standard Operating Procedure
(SOP), following consultation with BCoPD's legal
counsel, training officers, Internal Affairs, and
command and staff officers. Additional directives
were added following the completion of instructor
training and writing of the lesson plan. The SOP
requires all members of BCoPD whose normal duties
include making arrests or supervising arrest
situations to carry OC spray. Uniformed members of
the department are to carry the device on their gun
belts in an issued holster, while nonuniformed
officers are to carry pen-sized containers after
completing a training program and demonstrating
their competence in handling and using the OC
spray.
Guidelines for usage. BCoPD, like most other police
departments, adheres to the use-of-force continuum
and its range of response, beginning with the mere
presence of an officer and escalating to the use of
deadly force. According to BCoPD procedures, OC
spray may be used by an officer in any arrest
situation when:
o The aggressor has failed to comply with the
officer's verbal instructions.
o The aggressor has been advised of OC's impending
use.
o The officer is about to use hands-on tactics to
defend himself against active hostile resistance.
o The officer is confronted by an aggressive
animal.
BCoPD thus places the use of OC spray above verbal
commands on the force continuum as a means of
control and restraint. BCoPD emphasizes that OC is
not a substitute for a firearm. If, when faced by
an armed individual, the officer deems deadly force
necessary, then BCoPD considers the firearm to be
the weapon of choice.
During the study, patrol officers voiced concern
about whether they would be allowed to use deadly
force if attacked with OC spray. The Legal Officers
Section of the IACP holds that an officer may use
deadly force to protect himself from the use or
threatened use of OC spray when reasonably sure
that deadly force will be used against him if he
becomes incapacitated. Incapacitation includes
situations in which officers may be unable to
adequately defend themselves due to the effect of
chemical sprays. Criteria for determining when to
use deadly force incorporated situations in which
OC was used against police (see "Reasonable Use of
Deadly Force").
The Baltimore County Police Department operating
procedures also outlined how to use the product and
decontaminate the prisoner after use. The SOP
directs officers to assure the suspect of the
temporary nature of OC's effects and to provide air
and water as first aid. BCoPD officers were
instructed to remove the sprayed subject from the
spray area into fresh air and to allow access to
"copious amounts" of water, as soon as possible.
Since BCoPD patrol vehicles did not carry water or
any special equipment to aid in the decontamination
process, they relied on physically removing
suspects, instructing sprayed persons not to rub
their eyes, and transporting them quickly to a
source of water.
Use of pepper spray
During the study period, Baltimore County officers
used OC in response to 194 (174 human and 20
animal) incidents, which fell into various
categories of complaints that beat police officers
often handle. These types of complaints usually
involved aggressive, excitable behavior on the part
of both the complainant and victim. Moreover, they
tended to escalate quickly, resulting in
confrontational outcomes.
Thirty-nine percent of the incidents occurred
inside some structure (e.g., house, car), while the
remaining incidents occurred "out-of-doors."
Weather conditions did not seem to influence either
an officer's decision to use OC or the spray's
effect on suspects. Eighty-four percent of the
human subjects sprayed were male and 16 percent
were female. Generally, sprayed individuals were
intoxicated (drugs or alcohol), belligerent, and/or
combative. The majority (89 percent) of incidents
involved suspects who physically threatened the
police officer; very few incidents involved the use
of firearms or knives. The arrest/intervention
incidents necessitating the use of the spray were
primarily battery, assault, and disorderly conduct
(see exhibits 1 and 2).
Effectiveness of OC use
Overall, OC was very effective in the 194 incidents
where it was used (see "Officers' Comments on OC"
on page 6). A total of 156 (90 percent) of the 174
individuals sprayed were incapacitated enough to be
effectively arrested. Data indicate that almost all
officers applied OC to the suspect's face, as they
had been directed in training. However, officers
generally did not spray from a distance of 4 to 6
feet as instructed. In 144 incidents, the spray was
activated at a distance of 3 feet or less; in 102
of these, OC was sprayed at a distance of 2 feet or
less. As a result, OC may not have been maximally
effective.
Yet the data show that OC worked even if it was not
sprayed from the distance suggested by the
manufacturer. In 144 incidents, only one spray was
required to incapacitate a subject; officers used
the full contents of an issued container of OC to
control suspects in four separate incidents. No
data indicated that spraying more than one short
burst produced better effects, if the subject were
given a "good" spray the first time. The data
showed that 117 individuals (67 percent) were
classified by officers as submissive after the OC
had been applied; 27 individuals (16 percent) were
listed as complying with officer instructions after
being sprayed (see exhibit 3). The difference
between the terms "submissive" and "compliant" is
subtle,[2] and it might be more appropriate to
collapse the two categories into one. When the
categories are collapsed, 144 (83 percent) of the
174 subjects were sufficiently neutralized to yield
to officer orders. Thirty individuals (17 percent)
struggled or otherwise failed to follow officer
instructions.
Eighteen of these 30 struggling subjects were
classified by officers as not fully incapacitated
by the OC spray. According to officer reports, the
OC had no effect on seven suspects. These seven
individuals exhibited drugged behavior or seemed to
have emotional problems. These data indicate that
individuals who are heavily intoxicated, drugged,
or mentally unstable may be resistant or immune to
OC's effects or that OC may actually exacerbate the
difficulty associated with controlling such
persons.[3] Additionally, these types of encounters
may cause the officer to be cross-contaminated if
the incident escalates to a physical confrontation.
BCoPD's experience indicates that training officers
may want to stress the importance of accurately
assessing the likely impact of pepper spray in such
an encounter and of being prepared to select
another control alternative.
Animal control. Interest in OC's effectiveness in
animal encounters was high because, prior to
project implementation, BCoPD had experienced a
number of incidents where officers were forced to
shoot threatening or attacking dogs. During the OC
field study, dogs were sprayed with OC in 20
incidents where the animals posed a danger to
officers. Ten of the dogs sprayed weighed between
25 and 50 pounds, and 6 weighed more than 50
pounds.
Data showed that officers sprayed the dogs at
distances greater than those from which they
sprayed humans. The majority of dogs were sprayed
from a distance of 3 to 8 feet, whereas most humans
were sprayed from a distance of 1 to 3 feet. The
difference in application distances may account for
the differences in the effectiveness levels for
dogs and humans. OC was effective nearly 100
percent of the time in dog encounters (one officer
was bitten but required no medical treatment).
Other results of OC use
Assaults on officers. Three years of prior assault
data (pre-OC data) were collected for comparison
with data from the period after which OC was
adopted by the department (post-OC data). The
pre-OC data were examined to identify any possible
trends regarding assaults. Overall, these data
showed that officer assaults were decreasing prior
to OC use. The post-OC data indicated that assaults
continued to decline. In fact, the total number of
officers assaulted in the post-OC period was
substantially lower than in any pre-OC data period.
While it is likely that the introduction of OC
spray contributed to this significant decline, the
finding must be considered preliminary, since the
pre- and post-data for this study were not strictly
comparable in all cases.
Injuries to officers. Data from the spray
collection form showed that few officers were
injured when they used OC to control a
confrontational encounter. Only 21 officers (11
percent) reported receiving any injury (see exhibit
4). Most of these were minor and resulted in no
lost work time. Although data from the pre-OC use
period were not comparable and did not permit a
complete before-and-after analysis, the relatively
low level of injuries sustained by officers in the
post-OC period suggests that OC use has the
potential to reduce officer injuries in
confrontational situations.
Injuries to suspects. Very few suspect injuries
occurred during the post-OC project period. Of the
174 spray incidents, only 14 suspects (8 percent)
received any injuries, and all of these were minor,
requiring no hospital treatment (see exhibit 4).
Staff were not able to gather pre-OC comparison
data; however, it was hypothesized that if suspects
were injured, complaints of force would be filed
more often. The data collected during the study
period indicated that such complaints were
decreasing at a rate greater than that observed
prior to the introduction of OC. It is reasonable
to conclude that OC had a positive effect on
reducing the number of suspect injuries.
Use-of-force complaints. Departmental policy states
that a use-of-force report must be completed if the
subject complains of injury as a result of arrest
and goes to the hospital for medical treatment.
However, as is true for other less-than-lethal
weapons, a use-of-force report is not required for
OC, absent a complaint or hospital treatment. BCoPD
officials concluded that treating OC differently
could inappropriately hinder its use.
Data suggest that despite an increase in calls for
service and fewer patrol officers working their
beats, use-of-force complaints declined by 53
percent during the second pre-OC period (July 1991
through March 1992 ) and the post-OC period.
Similarly, a reduction of 40 percent occurred
between the third pre-OC period (July 1992 through
March 1993) and the post-OC period (see exhibit 5).
Since no other major policy changes regarding use
of force took place during pre- and post-data
collection, it is likely that the use of pepper
spray accounted for the decrease in complaints.
Interviews with Internal Affairs officers add
weight to this finding. These officers noted that,
unlike those of impact weapons, the effects of OC
are short-lived and nontraumatic; pepper spray thus
reduces the likelihood that brutality or excessive
force complaints would be lodged. In addition,
sprayed individuals received aftercare from the
officers who sprayed them, which may have obviated
the need to complain.
During the time of data collection (July 1993
through March 1994) and over the span of 174
sprayings, five complaints of brutality and one
use-of-force case were received by BCoPD. These
complaints centered on the officer's purportedly
inappropriate behavior and did not address the
spray itself. To date, BCoPD has not had any
complaints or suits filed that relate to the issue
of OC spray.
Summary
Most police departments in the United States are
concerned about officer and suspect safety. In
recent years, this concern has focused on injuries
to police officers and citizens during arrest
confrontations. To meet this problem, departments
have sought answers in technology involving
less-than-lethal weapons. Aerosol pepper spray is
one weapon from the LTL arsenal that effectively
addresses the issue of officer/citizen injury.
This study's findings indicate that BCoPD
successfully implemented its OC operation.
Statistical measurements of effectiveness were
high, and those related to officer assaults,
officer and citizen injuries, and use-of-force
complaints were low. Study findings showed that OC
spray offers advantages over more problematic
sprays and that a well-developed OC spray program
can provide a variety of operational benefits for
law enforcement agencies. In addition, the process
followed by BCoPD could guide other police
departments interested in OC implementation.
Notes
1. Granfield, John, Jamie Onnen, and Charles S.
Petty, M.D., Pepper Spray and In-Custody Deaths,
Executive Brief, Alexandria, Virginia:
International Association of Chiefs of Police,
March 1994.
2. The terms "submissive" and "compliant" were used
by officers completing the data collection form. An
individual officer's understanding and expectation
of OC's effect on a suspect may cause him or her to
make a distinction between the terms. Officers who
believe that the purpose of OC is to totally
incapacitate a subject, with no resistance, might
describe the suspect as submissive and conclude,
therefore, that the product worked. If the OC did
not perform as expected, the same officer might
report that the product had no effect -- despite
the fact that the suspect was easier to arrest as a
result of being sprayed. Other officers might
believe that the product worked well, even though
the suspect offered a struggle. This discussion is
offered to caution against strict interpretation of
subjective responses.
3. More research is required to obtain definitive
answers to the question of how intoxication, drug
use, and/or mental illness affect a person's
reaction to OC spray.
------------------------------
Reasonable Use of Deadly Force When Officers Are
Attacked With OC
When a criminal attacks an officer with OC spray,
he does so with the intent to harm the officer,
escape, or both. It is common knowledge that a high
percentage of officers who are incapacitated or
have had their guns taken away are later shot with
their own weapons. To ask an officer to take a
chance that the OC spray attacker is going to walk
away after incapacitating the officer would be, in
the opinion of IACP's Legal Officers Section,
unconscionable.
In determining whether an officer's use of deadly
force was reasonable, the following factors may be
considered:
o The nature of the crime committed by the person
or persons confronting the officer.
o The nature of the verbal or physical threats
posed by the person confronting the officer.
o The relative strength and fighting skills of the
officer and his opponent.
o The number of officers versus the number of
potential assailants.
o The nature of weapons in the possession of or
available to the assailant.
o The ability to circumvent the potential effects
of OC spray.
o The alternative means of defending against the
use/effects of OC spray.
o The availability of assistance from other nearby
officers.
---------------------------
Officers' Comments on OC
The following comments were extracted from the OC
data collection sheets completed by the BCoPD
officers or from followup interviews:
o Wish we had had it a while ago.
o I think it's a great...alternative to initial use
of force.
o Definitely better than using a nightstick.
o The word is out (on the street)...all people have
to do is hear the Velcro (copyright) and they
comply pretty quickly. [The officer who made this
comment had actually pulled the OC from his holster
at least 10 times, but had sprayed it only once.]
o Some subjects actually apologize after being
sprayed.
------------------------------
Findings and conclusions of the research reported
here are those of the authors and do not
necessarily reflect the official position or
policies of the U.S. Department of Justice.
The National Institute of Justice is a component of
the Office of Justice Programs, which also includes
the Bureau of Justice Assistance, Bureau of Justice
Statistics, Office of Juvenile Justice and
Delinquency Prevention, and the Office for Victims
of Crime.
------------------------------
NCJ 162358
The full report summarized in this Research in
Brief was prepared by Steven M. Edwards, John
Granfield, and Jamie Onnen under National Institute
of Justice grant number 92-IJ-CX-K026. The authors
were with the International Association of Chiefs
of Police while conducting their evaluation.
Questions about the full report may be directed to
John Firman, research coordinator, IACP.
------------------------------
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