Journal No. 254 • July 2006
Body Armor Safety Initiative: To Protect and Serve
by Dan Tompkins
On December 23, 1975, Seattle Police Department Patrolman
Raymond T. Johnson stood in the checkout line at a local
market when a robbery suspect entered the store and brandished
a weapon. Johnson lunged for the suspect’s gun. In
the violent struggle that ensued, the suspect emptied his
.38 caliber pistol, striking Johnson in the left hand and
twice in the chest before fleeing.1
Johnson survived with severe hand injuries, chest bruises,
and a unique distinctionthe first law enforcement
officer saved in a field test of a new generation of soft
body armor being conducted by the National Institute of
Johnson was wearing body armor made with Kevlar®,
an extraordinarily strong fabric developed by DuPont. NIJ,
in partnership with the U.S. Army, began a program in the
early 1970s to develop lightweight body armor woven from
Kevlar®. Field testing
began in the summer of 1975, with 5,000 armors provided
to 15 urban police departments. Less than 6 months later,
Johnson was the first officer saved by one of the field
test armors. In all, 17 other armor-wearing officers were
saved during the 1-year field test.
About the same time, NIJ developed a performance standard
for body armor in collaboration with the National Institute
of Standards and Technology (NIST, then known as the National
Bureau of Standards),2
followed by a voluntary testing program. The standards and
testing program, which still exists today, enables body
armor manufacturers to certify the performance and safety
of new body armor.3 The
NIJ standard establishes minimum performance requirements
for armor, and the testing program evaluates armor against
Twenty-eight years later, on the night of June 23, 2003,
Forest Hills, Pennsylvania, Police Officer Edward Limbacher,
wearing body armor constructed primarily of a fiber called
Zylon®, threw open
the side door of an unmarked Econoline van and stepped out
to move in on a drug suspect. The suspect fired, striking
Limbacher in the arm and abdomen with .40 caliber rounds.
The shot to the abdomen penetrated the body armor Limbacher
was wearing. He survived but sustained severe injuries.4
The Forest Hills shooting was the first case ever reported
to NIJ in which body armor compliant with the NIJ standard
failed to prevent penetration from a bullet it was designed
In the 28 years between those two incidents and in the
time since, at least 3,000 officers survived shootings or
other incidents because they were wearing body armor meeting
NIJ performance standards.5
But the Forest Hills incident caused great concern within
the law enforcement community and within the U.S. Department
of Justice: Are we keeping our officers safe?
The Body Armor Safety Initiative
In November 2003, in the aftermath of the Forest Hills
incident, then Attorney General John Ashcroft announced
a Body Armor Safety Initiative to address the reliability
of body armor used by law enforcement and to review the
process by which body armor is certified.6
As part of the initiative, NIJ tested both new and used
ballistic-resistant vests made with Zylon®.7
NIJ also tested upgrade kits distributed by the manufacturer
of the armor in the Forest Hills incident to retrofit some
models of its Zylon®-based
vests. And NIJ began a review of its standards and testing
program for ballistic-resistant vests, which has resulted
in interim changes to the standards and testing process.
Read on for the results of these tests and a summary of
changes to the standards and testing program.
Why Did the Vest Fail?
Even before the announcement of the Attorney General’s
initiative, NIJ staff contacted representatives of the Forest
Hills Police Department and the Allegheny County Police
Department (the agency handling the criminal investigation
of the shooting) to examine the vest, the weapon, and the
ammunition used in the shooting to determine why the vest
failed. The examination found that:
- The bullet velocity from the gun
used in the shooting was not greater than the bullet velocity
NIJ uses in compliance testing for the type of vest Limbacher
- The physical properties of the bullets
used in the shooting were similar to bullets used in NIJ’s
compliance testing of the type of vest Limbacher was wearing,
although there were some differences in bullet geometry
and in how the bullet deformed on impact.
- The tensile strength of Zylon®
yarns removed from the back panel of Limbacher’s
vest was up to 30 percent lower than Zylon®
yarns from new armor that the manufacturer provided for
this study. (The front panel, which was penetrated in
the incident, was being held as evidence in the criminal
case against the shooter, so it was not available for
NIJ also developed a detailed test plan simulating the
Forest Hills incident to isolate the factors deemed most
likely responsible for the vest failure. Test designers
identified five potential causal factors: ballistic material
tensile strength, bullet type, the gun barrel twist, the
shot angle, and the location of the shot on the armor.
NIJ obtained and tested 32 ballistic panels of the type
worn in the Forest Hills incident. Half of the panels were
tested new, and the other half were artificially aged for
5 months in a chamber exposing the panels to controlled
temperature and humidity conditions until the tensile strength
of fibers in the vests matched those of fibers from the
rear panel of the Forest Hills vest.
Each of the 32 panels was shot six times. None of the 192
shots penetrated the panels. NIJ is continuing efforts to
determine the cause of the Forest Hills failure but is still
unable to draw a definitive conclusion.
Testing the Upgrade Kits
As part of the Attorney General’s initiative, NIJ
was directed to test any upgrade kits offered by body armor
manufacturers to retrofit existing vests. The tests would
determine if the upgrade kits met the NIJ performance standard
when used with the original vest they were designed to supplement.
One manufacturer, Second Chance Body Armor, Inc. (the manufacturer
of the body armor worn in the Forest Hills incident), offered
an upgrade kit to users of some models of Zylon®-based
body armoran additional ballistic panel to be inserted
into the armor. At NIJ’s request, Second Chance provided
50 sets of armors and matching upgrade kits for three soft
armor protection levelsLevel IIA, Level II, and Level
IIIA.8 The samples included
both new and used upgrade kits, and the majority of the
armors had been previously worn.
NIJ’s testing found that the Second Chance upgrade
kits added protection when used with the existing used body
armor. However, the level of protection did not meet existing
NIJ performance standards for new body armor.
Also, the vest/upgrade kit combinations in all three protection
levels experienced excessive “backface signatures.”
This means that the bullets didn’t penetrate the vest,
but the impact of one or more bullets created a “dent”
of more than 44 mm (almost 2 inches) into the clay in back
of the vests during testing, a depth that may cause serious
injury. Six of eight Level IIA armors, two of eight Level
II armors, and five of eight Level IIIA armors ultimately
tested experienced excessive backface signatures during
Further, two of the eight Level IIIA vest/upgrade kits
(designed to offer protection against high velocity 9 mm
and 44 magnum bullets) experienced penetrations.
Despite the safety questions raised by these test results,
it is important to note that the upgrade kits did add some
measure of protection. Officers who have received these
upgrade kits should wear them.
Testing Used Armor
Heat, moisture, ultraviolet and visible light, detergents,
friction, and stretching may all contribute to the degradation
of fibers used in the manufacture of body armor. Body armor
manufacturers design their armor and provide care instructions
to minimize the effects of these degrading properties.
Because the evidence showed an unexpected degradation rate
in Zylon®-based armor,
NIJ conducted ballistic and mechanical properties testing
on 103 additional used body armors containing Zylon®.
Law enforcement agencies across the United States provided
these vests to NIJ. Sixty of these used armors (58 percent)
were penetrated by at least one round during a six-shot
test series. Of the armors that were not penetrated, 91
percent had backface deformations in excess of that allowed
by the NIJ standard for new armor. Only four of the used
armors met all performance criteria expected under the NIJ
standard for new body armor compliance. Although these results
do not conclusively prove that all Zylon®-containing
body armor models have performance problems, the results
show that used Zylon®-containing
body armor may not provide the intended level of ballistic
In addition, armors were visually inspected and given one
of four condition ratings from “no visible signs of
wear” to “extreme wear and abuse.” Testers
found no correlation between the level of visible wear of
the body armor panels and the ballistic performance of those
panels. This finding is important because even used Zylon®
body armor that appears to be in good condition may not
provide an acceptable level of performance.
Exploring Fiber Degradation
With funding provided by NIJ, polymer scientists at NIST
are probing down to the molecular level to learn more about
how Zylon® degrades.
They are examining the chemical changes that occur as the
fibers degrade, the trace contaminants on fibers that may
contribute to degradation, the moisture content of fibers,
and mechanical strength differences among individual fibers
and what causes those differences.
Initial findings have isolated the ballistic performance
degradation to the breakage of a small part of the Zylon®
fiber molecule. Breakage of this part of the molecule, called
the oxazole ring, occurs as a result of exposure to both
moisture and light. When there was no potential for external
moisture to contact Zylon®
yarns, there was no significant change in the tensile strength
of these yarns. Therefore, it appears that external moisture
is necessary to facilitate the degradation of Zylon®
In addition to this work, NIJ is also funding research
on other personal protective equipment to better understand
how and why ballistic-resistant materials degrade over time.9
Improving the NIJ Standard and Compliance Testing Program
NIJ has undertaken a complete review of its performance
standard for ballistic-resistant armor and the compliance
testing program. It solicited input from law enforcement
and corrections agencies, fiber and armor manufacturers,
and standards and testing organizations.
NIJ’s 2005 Interim Requirements for Bullet-Resistant
Body Armor, issued in August 2005, take into account the
possibility of ballistic performance degradation over time.
These interim requirements will help ensure that officers
are protected by body armor that maintains its ballistic
performance during its entire warranty period.
Under the 2005 interim requirements, NIJ will not deem
armor models containing PBO (the chemical basis of Zylon®)
to be compliant unless their manufacturers provide satisfactory
evidence to NIJ that the models will maintain their ballistic
performance over their declared warranty period.
NIJ recommends that agencies that purchase new ballistic-resistant
body armor select body armor models that comply with the
NIJ 2005 Interim Requirements. A list of models that comply
with the requirements is maintained at:
NIJ is also encouraging manufacturers to adopt a quality
management system to ensure the consistent construction
and performance of NIJ-compliant armor over its warranty
period. In the future, NIJ will issue advisories regarding
body armor materials that appear to create a risk of death
or serious injury as a result of degraded ballistic performance.
Any body armor model that contains any material listed in
such an advisory will be deemed no longer compliant with
the NIJ standard unless the manufacturer satisfies NIJ that
the model will maintain ballistic performance over the declared
There are at least 3,000 other stories like that of Seattle
Police Officer Raymond T. Johnson. That’s 3,000 families
spared the anguish of death or debilitating injury to a
loved one in the line of duty. And cases like that of Forest
Hills Officer Limbacher’s are rarea testament
to the reliability of soft body armor. Even so, that single
failure prompted NIJ to review its body armor program and
to conduct an intensive examination of why that failure
occurred. Through this review and research, NIJ remains
committed to working for the safety of law enforcement officers.
The evidence is clear: An officer not wearing armor is
14 times more likely to suffer a fatal injury than an officer
who is. Therefore, the most important message for the law
enforcement community is that officers should continue to
wear their body armor.
At least 3,000 officers would second that advice.
For More Information
- The suspect was arrested 6 weeks later and charged with
first-degree assault and attempted robbery. He was convicted
and sentenced to 15 to 30 years’ imprisonment.
- Commercial body armor was being manufactured and sold
even as NIJ’s field test began, accelerating the
need for a standards program. In fact, the first documented
“save” unrelated to NIJ’s field test
occurred in May 1973 in Detroit, Michigan.
- More information about NIJ’s
body armor standards and testing program can be found
at NIJ’s National Law Enforcement and Corrections
Technology Center Web site, JUSTNET.
- The suspect fled but was arrested later that night.
In April 2004, he was convicted of 2 counts of attempted
homicide, 11 counts of aggravated assault, and 9 counts
of reckless endangerment related to the June 23, 2003,
- In 1987, DuPont and the International
Association of Chiefs of Police (IACP) created the Kevlar
Survivor’s Club, which recognizes law enforcement
and corrections officers who survive life-threatening
or disabling events because they were wearing personal
protective body armor. In March 2006, IACP commemorated
Atlanta Police Department Officer Corey B. Grogan as the
3,000th documented save. A Website keeps a tally of survivors, maintains a database
of survivor stories, and provides criteria and instructions
- A Web site supporting the Body Armor
Safety Initiative is located at www.ojp.usdoj.gov/bvpbasi.
- Zylon fiber is manufactured by Toyobo Co., Ltd., of
- For a description of the protection
levels, see NIJ’s
Ballistic Resistance of Personal Body Armor, NIJ Standard-0101.04.
- The most recent NIJ solicitation for concept papers,
“Officer Safety Equipment,” is available at