The explosion happened without warning around 4 a.m. in West Chester, Pennsylvania.

FBI agent Donald Bain was sitting in his car in a parking lot with two other agents. He was armed and wore a Kevlar vest. He was also carrying a “flash-bang” grenade, a nonlethal weapon that emits a bright flash and deafening bang that’s used to shock and disorient criminal suspects or the enemy in combat situations…

That’s when, Bain says, the flash-bang grenade in his vest just blew up.

“The car is on fire,” Bain recalled. “I was told later I was on fire. Smoke billowing in the car. It was obviously chaos…”

Bain suffered severe bruising, a concussion and burns to his neck and ears. All three agents said they have experienced hearing loss.

The company that manufactured the flash-bang grenade that Bain used is Pyrotechnic Specialties Inc., also known as PSI, based in Byron, Georgia.

Earlier this year, PSI, its chief operating officer, David Karlson, and three other defendants were indicted for fraud, conspiracy and money laundering. According to the federal indictment, PSI had a $15 million contract to supply flash-bang grenades to the military before it supplied them to the FBI.

The indictment states the company knew its flash bangs were defective and even knew how to fix those flaws, which would have cost PSI $3.72 per unit.

Their lawsuit is being handled by an attorney also suing on behalf of a sergeant who lost a hand from one of these crappy explosive devices.