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The Navy working uniform's 50/50 blend of nylon and cotton is known in the industry as NYCO. It has many advantages as a fabric, including strength and moisture-absorption, but textile and fire-safety experts cautioned this material has one huge downside: inability to withstand heat.
"I was shocked when I looked at this report," said Hoon Joo Lee, a textile engineering expert at North Carolina State University, who reviewed the recent Natick flame test results. "I can't believe the Navy is using NYCO for their working uniform. What's going to happen if there's a fire on the ship?"
Lee, who has consulted the Army on combat uniforms, explained that NYCO lacks flame resistance because the cotton burns and the nylon melts, a combination that renders the fabric unfit for proximity to heat or flame. Nylon is a synthetic material, like polyester, whose thermoplastic fibers are produced from petroleum. Heat melts these fabrics.
Depending on the blend, nylon melts at temperatures as low as 374 degrees, Lee said.
"You don't want to go too close to fire wearing this," Lee added.
And yet that's exactly what the Naval Safety Center declared was OK last year.
Safety officials cleared the fleet last year to fight fires in NWUs, especially in the critical moments after a fire is first discovered — when you have the best chance to extinguish it.
"The urgency for immediate response demanded by a shipboard fire requires that a sailor wearing the NWU be prepared to attack a newly discovered fire in order to extinguish the fire or prevent fire spread," the Naval Safety Center said in an Oct. 6, 2011, safety advisory. "In other words, initial response can be in the NWU uniform."
Neither fleet officials nor the Naval Safety Center had revised this guidance as of Dec. 14.
Utility coveralls, the blue uniform worn throughout the fleet, will also melt and burn in a fire, said two textile and fire experts consulted by Navy Times. This uniform has 65/35 polyester-cotton fabric and is not treated with a flame-resistant coating. That's the only thing that could keep this uniform from melting and burning, they said.
Dr. Peter Hauser, a textile chemist at North Carolina State University, reviewed the utility coveralls fabric specifications provided by the Defense Logistics Agency.
"Polyester is a thermoplastic polymer just like nylon," Hauser told Navy Times, adding that he has worked for years to develop flame-resistant treatments for these fabrics. "If it's not treated, it's going to burn and melt and drip."
Another expert agreed. If this fabric was also flame-tested, it would almost certainly exhibit the same characteristics as the NWUs, said Guy Colonna, a chemical engineer with the National Fire Protection Association. It has two issues, he explained: "One, it doesn't exhibit fire-resistance characteristics, and two, it shouldn't be used as a primary garment for people who are expected to be routinely in and around the potential for fire."
Blazes are best fought by expert fire crews, such as the ship's "flying squad" of damage controlmen, outfitted in the Navy's fire-fighting ensembles, complete with coat, helmet, flash gear and durable boots. Since NWUs lack flame resistance, they are not suited for fire-fighting and may only be appropriate for putting out a trash can-sized fire.
Hauser said it was probably OK to fight a small fire, the kind that could be doused with a hand-held extinguisher.
"But if you're talking about a whole compartment on fire," he continued, "then it'd be a different situation. Or if, for example, you had an aviation fuel fire, which would be a lot more intense. Then you wouldn't want somebody wearing this to be involved."
Hauser compared nylon melting to super-hot melted candle wax. Chemists are working to develop flame-resistant treatments for nylon that would prevent melting and dripping, he said. But as it stands, the test shows this uniform is not suited to fight fires, said Hauser and another fire safety expert who reviewed the Natick test results.
The NWU "doesn't provide fire-resistance characteristics and performance and therefore shouldn't be used in that kind of environment," said Colonna. "If the condition of their work activity is to respond to fires, it would seem that based on these test results, that's counter to the ability of the actual uniform to survive that kind of environment."
Another risk: Sailors encounter flammable substances all the time. They can be in anything from the paint and cleaners found in storerooms and paint lockers to the fuel and oil in engine rooms. If flammable substances aren't carefully removed from the garment, they can put the wearer at risk of having the uniform ignite, Colonna explained.
Sailors in NWUs are at risk of fighting fires in that uniform and will only be better protected by flame-resistant clothing, including garments such as the firefighting ensembles, flight suits and engineering coveralls.
NWUs, when worn under the firefighting ensemble, would likely be safe, said Colonna, a former Coast Guard officer who added that the Navy needs to provide sailors with updated guidance on what's safe.
"There needs to be some conversation in terms of education for everybody about the differences and the protection that they have and the level of risk or the level of hazard that they escalate through as they go through these different levels of clothing," Colonna said.
To many in the fleet, the news that NWUs melt feels like a step backward, a sign that the Navy has forgotten the lessons after hundreds of deaths from devastating shipboard fires, one commander said.
"I would think that fire-resistance would have been the number one criteria for evaluation a new working uniform," said Cmdr. Andrew Thaeler, who's assigned to the Naval Postgraduate School, in an email to Navy Times. "How is it that the [Marine Corps] and Army have safer uniforms given the much higher risk of fire in [Navy] shipboard environments?
"We need to move to a fire-resistant uniform immediately," he added. "After reading this report, I'd feel much safer wearing [a Flame Resistant Army Combat Uniform] on a ship than NWUs."