The U.S. Navy’s newest coverall passed its first flame test — one that wasn’t scheduled.

Hull Maintenance Technician 3rd Class Ryan Davis was working with a grinding wheel that, unbeknownst to him, was shooting hot sparks onto his coveralls, according to Navy Times. Fifteen minutes of sparks only left a small hole in Davis’ coveralls and “showed what the new coveralls don’t do — rapidly burn and melt.”

Utility coveralls, like the Navy working uniform, are not flame-resistant and have synthetic threads that are susceptible to melting. A startling Navy test in 2012 found that the blue-and-gray NWU quickly catches on fire and will burn until engulfed.

After studying those concerns, fleet bosses fast-tracked the new coveralls to boost sailors’ fire-protection. They are made of the same fabric as the damage control coveralls issued out of repair lockers: 100 percent cotton treated with an FR coating.

The Navy began issuing sets a year ago and has nearly finished the initial outfitting. Over 325,000 pairs of coveralls have been issued to sailors assigned to ships and squadrons, clothing an estimated 92 percent of fleet sailors, according to figures from Fleet Forces Command. Submarine sailors are still wearing utility coveralls as officials search for a low-lint material that will meet their requirements.

For more on the new coveralls, please visit NavyTimes.com.