Does Your Vest Cause You Unrest?

A well-known manufacturer has come under fire amid great concern regarding the reliability of its Zylon-based body armor vests.

First published in Police & Security News, May/June 2004

When first brought to market in 1998, Zylon was apparently a perfect ballistic fiber: it offered better strength than other fibers at a fraction of their weight. But the “miracle” fiber had one serious flaw: it degraded much faster and more severely than other fibers under everyday environmental conditions. Worse, it took tragedy to make the problem apparent. One officer was killed and two others wounded when bullets penetrated their Zylon vests.

The resulting lawsuits have asked questions whose answers aren’t coming easily. Did the vests’ manufacturer knowingly sell a defective product, or was it coincidence’s unfortunate victim? Why haven’t other manufacturers reported problems with their Zylon-based vests? And can Zylon’s problems ever be resolved?

How it all started

Zylon, manufactured by Japan-based Toyobo Co., Ltd., is currently used in body armor, safety gloves, firefighters’ heat resistant turnout gear, and racing suits and cars, and many other applications. Its strength as a ballistic fiber is shown by the MIL-SPEC 622E standard, also known as the V50 test. The standard shows the velocity, in feet per second (fps), a bullet must travel before it’s 50 percent likely to penetrate a vest. “The higher the V50, the better the fabric is at stopping a bullet,” says Allen Price, president and CEO of U.S. Ballistic Engineering, Inc. and a Toyobo spokesman. Zylon's V50 is 2000 fps, compared to a V50 of 1500 fps for aramid (Kevlar, Twaron) and 1550 fps for polyethylene (Spectra, Dyneema) fibers.

Kent Jarrell, the U.S. representative for Toyobo, says the average weight of a National Institute of Justice (NIJ) Level IIIA-certified Zylon vest has declined by 25 percent, from about 1.1 pounds per square foot (lbs./ft2) to just .85 lbs./ft2. And, says Price, just .69 lbs./ft2 of Zylon can defeat a bullet traveling at the NIJ’s Level IIIA threat standard speed of 1400 fps. That’s the lightest weight for that kind of stopping power.

Furthermore, even a hybrid vest containing just five percent Zylon makes a difference in weight: a vest using only the other fibers weighs about .85 lbs./ft2, compared to .75 lbs./ft2 for a Zylon hybrid. Jarrell notes that the wear rate of Zylon-based vests has increased by 20 percent owing to their comfort, light weight, and flexibility.

Second Chance Body Armor, Inc., with a solid reputation for saving lives and a 40 percent market share in the body armor industry, in 1998 contracted with Toyobo to become the first American company to manufacture Zylon vests; to date, its Ultima line of Zylon-based vests have saved over 30 lives. In 2001, other manufacturers began using the fiber. By March 2004, according to the NIJ, 16 manufacturers had certified nearly 240 Zylon-based ballistic vest models, and over 240,000 Zylon-based vests were in use. Still, Second Chance was the only American manufacturer offering pure Zylon vests alongside hybrids.

Gregg Smith, Second Chance spokesman, says the company received “excellent” feedback from officers about the Zylon vests. “Ever since soft, concealable, and wearable ballistic vests were introduced in the early 1970’s, many of the earlier models have been uncomfortable to wear,” he says. “But when Zylon came along, the officers found they could wear it almost like a t-shirt.”

A short-lived miracle

Zylon’s “miracle” status was short-lived. In June 2003, three officers’ Second Chance Ultima IIA Zylon vests failed in three separate incidents. Ed Limbacher, a Forest Hills (Pennsylvania) police officer, was shot in the stomach during a drug sting. His vest was just seven months old. In Ravalli County (Montana), sheriff’s deputy Bernie Allestad was wounded during a shootout. And Oceanside (California) Officer Tony Zeppetella was shot 13 times and killed. His Second Chance vest, which sustained three penetrations, was only eight months old.

The reason the vests failed was a characteristic of the Zylon fiber itself: when exposed to light, heat, and humidity, its tensile strength degrades, a chemical process called hydrolysis or thermal cycle degradation. Toyobo discovered this tendency in 2001, after Baumann & Steffen Sicherheitstechnik (BSST) GmbH, a German body armor manufacturer, and a rope manufacturer called Toyobo’s attention to the problem. (Asked why it wasn’t discovered in the three years after Zylon’s introduction, Jarrell says its original maker, Dow Corp., had tested it for hydrolysis in the 1980’s and found no problems.)

Price adds that degradation due to environmental causes isn’t unique to Zylon. Kevlar and Twaron are moisture-sensitive; Dyneema and Spectra, heat-sensitive. Smith adds, “All fibers degrade over time. That’s why manufacturers only guarantee their vests for up to five years. [Kevlar maker] DuPont and the NIJ set that industry-wide standard.” But Price notes that those fibers’ limitations were discovered and resolved in a matter of months. Why weren’t Zylon’s problems resolved sooner?

Zylon and tort law

Although Toyobo and Second Chance blame each other for the vests’ failure, the courts will ultimately determine fault. Greg Emerson, attorney for the Zeppetella family, calls Toyobo’s disclosure of Zylon’s problems a “double-edged sword.” “They did make the disclosures, but they did it knowing the fiber was being used. That’s the theory behind product liability – if a company knows its product is defective, it has the responsibility to place conditions on how that product is used.” An example would be stipulating that Zylon must be used only in hybrids with other materials. “They didn’t do that,” Emerson notes. “They continued to work with Second Chance to market and sell a defective product.”

“We believe Zylon is not defective,” Jarrell says. “We continue to manufacture and sell the product, and people continue to buy it. We’ve never pulled it from the market. We knew of its limitations – all fibers degrade over time – but we felt its flaws could be designed around. We advised the manufacturers to take this into account when designing their vests.”

Inconsistent test results

Second Chance asserts that Zylon alone is the problem, and that it’s an industry problem. They argue Toyobo’s 2001 testing was “unrealistic,” so they couldn’t determine its relevance to their customers. “Toyobo informed us in July 2001 that they’d seen a five percent loss in strength over ten years [owing to accelerated aging] at room temperature,” says Smith. “Obviously, this doesn’t have much relevance to an officer working in Tucson or Honolulu. Later, they updated their information to reflect a ten percent loss in strength at 104 degrees Fahrenheit, 80 percent relative humidity over ten years. At this point, Second Chance started recalling some vests for testing.”

Second Chance’s initial tests, including the V50 test, showed nothing alarming in a sampling of 200 vests from 37 law enforcement agencies in 19 different states. It wasn’t until summer 2003 – at the same time the shootings occurred - that preliminary signs of degradation appeared. Though inconsistent, the findings led to Second Chance’s decision in early fall of last year to discontinue its Ultima and Ultimax lines of Zylon-based vests.

“We don’t know why the initial tests showed no problems,” says Smith. Mark Pickett, Second Chance vice president of sales and marketing, speculates it’s because the vests had aged. Price says, “We believe the degradation could be the result of an armor system design defect that allows environmental exposure during wear.” Indeed, the NIJ’s preliminary investigation of Limbacher’s vest showed dramatic degradation compared to its archived test vest and a new Second Chance Zylon vest.

That Second Chance’s testing uncovered inconsistencies isn’t so far-fetched considering similar results from other companies. Mehler Vario Systems GmbH, another German body armor manufacturer, conducted a “wearer trial” of six vests that showed performance drops ranging from mild to severe. So did U.S. Armor, Inc.’s testing of 12x12 squares of material. And a recent test at NIJ-certified HP White Laboratories, Inc. showed degradation occurring before the five-year warranty period of some non-Zylon vests not manufactured by Second Chance.

These results may not mean much. Neither the Mehler nor the HP White tests can be considered scientific, because their samples – six vests per test – were too small to provide statistically significant evidence. Furthermore, Price says he’s seen only summaries, not actual data, from the Mehler and Second Chance tests. And the HP White test doesn’t mention the failed vests’ physical conditions.

Still, these issues may not be enough to make a strong case. The NIJ is testing much larger samples; test results showing performance decreases of 15 percent over eight weeks (according to Mehler) or 10 to 20 percent over six months to two years (from a Toyobo study) are dramatic. So is Mehler’s statement that its vests’ protective performance decreased “in a way [that] was not seen with normal [polyethylene] or Aramid panels.” Mehler and BSST both pulled their Zylon-based products from the market because they couldn’t guarantee the vests would remain protective for five years.

Furthermore, Georg Olsen, general manager at U.S. Armor, says seeing even inconsistencies was enough for U.S. Armor to decide not to take a chance on Zylon. “The results were too strong to ignore,” he says. “We lost a lot of sales as a result of deciding not to include Zylon, but we stood by what we felt was the right thing to do.” U.S. Armor was the only major body armor manufacturer never to use Zylon in its products: by the time Toyobo’s exclusive license to Second Chance and Armor Holdings expired, Zylon’s limitations were coming to light. “We were also seeing lots of odd little ‘smoke and fire’ warnings,” he says, “like the weavers asking us to sign a release of liability if we bought Zylon, and the negative performance charts coming directly from Toyobo themselves.”

The NIJ looks for answers

In a preliminary report from March 2004 (http://vests.ojp.gov/docs/ArmorReportWithPress.pdf), the NIJ acknowledges Zylon’s tendency toward degradation, but couldn’t say for sure whether the degradation had caused Limbacher’s vest penetration. Additional NIJ testing, begun in December 2003, on 20 used Zylon vests revealed that although they “appeared” serviceable, half were penetrated. But even this number isn’t statistically significant. By the end of 2004, the NIJ expects to have tested a much larger sampling of ballistic vests “from various climatic regions, age categories, and manufacturers,” reads its report. “This testing will seek to determine whether Zylon-based armor degrades, the general extent of the degradation, and what factors may be causing the degradation.”

The NIJ’s report remarks that a number of variables make controlled testing of used vests difficult at best. These include the way the vest’s owner cared for it (or didn’t), the type of climate it’s worn in, and manufacturing processes and materials. However, the NIJ was able to come up with a test protocol accounting for these variables “in an effort to determine which, if any, adversely affect the ongoing performance of armor in the field.” The protocol includes:

• Worst-case conditions. Heavy wear, heat, humidity, moisture, ultraviolet light, and improper care among other factors can contribute to degradation.
• Comprehensive testing. “In Phase II, approximately 500 armors will be randomly selected for testing from 5 different climatic regions, 5 different age categories, and 4 different manufacturer categories.
• Additional testing. If the data from the first two phases provide consistent conclusions about “a certain combination of factors (i.e., manufacturer X, model Y, age greater than Z years, specific design features, etc.), additional testing with similar samples may be needed to validate whether there is a true problem.”

Using these protocols, the NIJ believes it will learn what “definitively” causes Zylon to degrade, what happens to Zylon as it degrades, and ultimately how to monitor future armor degradation. Concurrently, the National Institute for Standards and Training (NIST), of the U.S. Commerce Department, will test the materials used to construct the vests. While the NIJ expects to complete its testing by the end of 2004, the NIST testing is likely to continue into 2005 or 2006.

What about hybrids?

Allan Main, marketing coordinator at Canadian manufacturer Pacific Safety Products, Inc., disagrees. After Toyobo’s 2001 disclosures, PSP, which has used Zylon in its hybrids since 1999, instituted a mandatory “Zylon Integrity Program,” regularly retrieving vests from the field for testing. “We’ve tested a number of vests, and not had any of the vests fall below expected performance. All tested vests have performed as expected,” says Main.

He couldn’t provide specific test data, but notes that the vests had been used for up to two and a half years. PSP holds to the industry standard five-year warranty. “The question isn’t just about Zylon’s performance,” says Main. “It’s about how body armor manufacturers are using the material, and whether the focus of some manufacturers on lighter weight is leading them to ignore product performance. There is a reason the PSP Zylon vest is heavier then a number of our competitors’.” PSP, for example, welds its vests “ultrasonically in a non-breathable waterproof nylon cover, a desiccant also sealed in with the panels,” says Main.

But Olsen contends even a hybrid is no guarantee of performance. Indeed, Armor Holdings, Inc. has recently been sued over its inclusion of Zylon in its hybrids. And Olsen believes it’s only a matter of time before the other hybrid manufacturers start to see Zylon degradation affecting their vests. “Say you have twenty layers of material in a vest, and only two are Zylon,” he says. “That’s ten percent of your vest experiencing a loss in stopping power. The Zylon was put in there for a ballistic purpose, which would be compromised.” Additionally, he says, Zylon could indeed be protected inside a totally sealed and self-contained panel – “if you could guarantee that the manufacturer and the weaver worked under the same conditions.”

Notably, Zylon is sensitive to fluorescent light, found in most manufacturing facilities, as well as moisture and humidity. And like all other fabrics, it retains a certain degree of naturally occurring moisture. Known degradation was the reason behind DuPont’s 3 to 5 year warranty and widely accepted “rational replacement policy” on Kevlar. “That was the point that the level of degradation, primarily due to ultraviolet light exposure, exceeded the safe margin of error built into the vest as determined by the V-50 tests they performed on used armor,” says Olsen. “Aramid vest usage history has proven this policy to be sound and effective.”

What the future holds

Conflict often foments change, and the body armor industry is no exception. “Every time there’s a controversy or the discovery of an issue, the industry has been able to improve the armor,” says Price. “When the NIJ first developed its stricter standard in the 1980’s, the manufacturers rebelled. They said the standard was too tough, that it would create the need to make heavier armor and in turn that police officers would stop wearing it. Instead new technology and techniques were introduced that resulted in lighter armor systems.”

In the cases of aramids and polyethylenes, the fiber manufacturers worked with the NIJ and body armor manufacturers to change the way the NIJ certified vests. Aramids’ moisture vulnerability led to NIJ wet testing; polyethylenes’ heat vulnerability, based largely on rumor, led to changes in the way vulnerabilities were reported.

Likewise, Zylon’s vulnerabilities are leading to two changes in NIJ test protocols: testing used vests, and testing additions to vests. Although the 1/10-inch panels that upgrade the Ultima and Ultimax vests haven’t been NIJ-tested due to a lack of protocol for vest inserts (augmentation panels), Smith expects this will be another change to the way the NIJ does things. The NIJ itself notes the changes in protocol. “During this time, NIJ will continue to review the existing process by which newly manufactured bullet-resistant vests are certified to determine whether the process should be modified.”

Price points out that soft concealable body armor ballistics is still a young science since its inception in the 1970’s. “Everything is drastically different now, and the NIJ is just trying to stay current,” he says. “Manufacturers need to be sure that armor being sold will in fact last for the full warranty period offered, or else change the warranty.” He believes the NIJ’s standard has done its job. “We need to fix what’s wrong now, but we need to know what happened before we can fix it.”

Sidebar: Ensuring Maximum Effectiveness from Your Ballistic Vest

Fraternal Order of Police Lodge 89, in Prince Georges County (Maryland) recommends police departments train officers to recognize that their vests are not “bullet proof” but only bullet resistant, and that they can extend their vests’ lives by protecting them from degradation. In a letter to lodge members, lodge president Percel O. Austin writes:

“Attempt to keep the ballistic panels as dry as possible. Do not leave your vest in a vehicle for prolonged periods of time. Protect your body armor from exposure to ultraviolet light.

“Inspect your vest on a regular basis, referring to the Personal Body Armor Inspection form (PGC [Prince Georges County] Form #4373). Check for irregularities, material bunching and/or excessive weight, due to the accumulation of moisture. Report problems in accordance to the General Orders.

“Make certain the ballistic panels are oriented correctly in the carrier. There should be a label that says “This side away from body”. It is crucial that the ballistic panels are placed in the carrier correctly for the highest level of protection.

“Read all of the manufacturer-provided literature that is issued with your body armor. This literature should explain proper fit, storage, care, cleaning and inspection of the ballistic panels and carriers.

“When you receive your body armor, complete the warranty registration form and return it to the manufacturer. This will ensure that you receive immediate notification from the manufacturer as to concerns or safety notices regarding the body armor you are wearing.”

Sidebar: Out of the Frying Pan

Part of police officers’ anger at Second Chance is based on the company’s policies and practices since the shootings occurred. For instance, Second Chance’s website acknowledges only Limbacher’s shooting but not Zeppetella’s. Smith says Zeppetella’s vest performed as certified. “The three bullets that penetrated the vest were all ‘edge’ shots, which NIJ protocol dictates isn’t enough to stop a bullet’s blunt-force trauma.” During NIJ testing, bullets are fired not less than three inches from the vest’s edge. “These are standards set forth by the NIJ as well as DuPont,” he says. “They know the industry, they know the technology, and this is what they’ve come up with as reasonable for certification.”

But Emerson, an attorney who works with the Los Angeles Sheriff’s Police Association, disagrees. First, he stresses that the NIJ protocol isn’t a standard measure for field-worn vests, merely a testing protocol definition of a “fair hit.” “The penetrating shots in Tony’s vest weren’t edge shots in the true sense,” he says. “They weren’t half holes. They were through and through, and the closest one to the edge is an inch and a half away. The one in the back isn’t even anywhere near the edge. If officers were to expect their vests only to perform according to NIJ standard, they’d have this tiny little square in the center of their bodies that would protect them.”

Moreover, he says, federal standards aren’t admissible in a product liability case anyway.
Another point of contention is Second Chance’s refusal to refund money spent on the vests. “Instead, the company gives officers the choice of a free upgrade involving the insertion of additional pads – neither tested by NIJ nor meeting NIJ standards – to assure vest performance throughout the warranty period, or to purchase at a discounted cost of $329 Second Chance’s top-of-the-line vest,” reads a November 2003 press release from the office of Senator Patrick Leahy (D-VT).

Smith says, “We’d like to offer free replacements to all our customers, but we just aren’t able to do it. We are doing the best we can. We’re offering the upgrades, which add a tenth of an inch front and back. We also offer the Monarch Summit replacement at minimum cost, which ends up being a 73 percent discount. A third option is for us to extend credit to officers based on the vest’s original price and how long it’s been in service.”

Addressing concerns that Second Chance has been “playing favorites” by replacing some vests for free and not others, Smith says this is because the company is simply honoring individual contracts with some agencies. As for the uncertified Kevlar Performance Pac add-ons, Second Chance has provided them to the NIJ for testing and certification. And, Smith says, before Second Chance introduced them, they were tested and approved at an independent, NIJ-certified test lab. NIJ describes its planned testing procedure on these as “similar” to the three phases of testing it will perform on full body armor.

Ultimately, Second Chance may not have a choice about full refunds. The consumer fraud action brought by the Arizona state attorney general’s office, along with other lawsuits, seeks to force the company to refund all its Zylon vests purchased since 1998. Moreover, Second Chance may lose the privilege of participating in the NIJ’s Bulletproof Vest Partnership Grant Program. Being barred from the program would result in significant losses for the company: the Leahy press release cites statistics showing that “8,344 suspect vests have been purchased to date. At a cost of about $875 per vest, at least $7,301,000 has been spent by officers and agencies on the vests purchased with matching federal grants from the Bulletproof Vest Partnership Grant Program.”

Related story

In a press release dated April 2004, shortly after "Does Your Vest Cause You Unrest?" went to press, the Minnesota Attorney General announced legal action against Second Chance. This time, though, the terms were different: Richard Davis had actually written documents stating he knew his Zylon vests were defective a year in advance of Tony Zeppetella's and Ed Limbacher's shootings.