Bette Sans Souci

Bette Sans Souci nicknamed Plastique by Cisco Ramon was a bomb specialist and metahuman.

Time in the Military
Bette was a sergeant for the US military as a bombs specialist (EOD, Explosive Ordnance Disposal). She was RTU'd from Afghanistan after a bomb went of and shrapnel got into her body. Dr. Hadley and Wade Eiling began performing experiments on her.

After the accident
Months after the particle accelerator accident, Bette stole a file from an office building and set off a bomb to escape, though she didn't mean any harm. Barry chased her down and Bette accidentally turned his suit into a bomb. Bette told Barry to take off his suit and his suit explodes soon after, though Barry got out in time. Bette later confronted Dr. Hadley, a Doctor who previously experimented on her with Wade Eiling. Wade intervened and attempted to capture her though she was merely wounded and saved by The Streak. At S.T.A.R. Labs, they realized that she had bomb fragments in her DNA, explaining why everything she touches turns into a bomb. When Caitlin checked up on her, she realized she was shot and noticed there was a tracker, where Wade shows up at S.T.A.R. Labs. The team managed to get Bette out of S.T.A.R. Labs as they monitored her powers outside the lab. While alone with Wells, she was told to go out and kill Wade. Bette had herself found by Wade where Wade knew she wasn't surrendering herself. Bette quickly attacked Wade and his men with bombs though The Streak arrived soon after. Bette was soon shot by Wade and tried to tell Barry that she was told by Wells to kill Wade but died before she could finish. The fragments in her DNA turned the bullet into a bomb but Barry managed to drop Bette's body into the river before she detonated.

Trivia

 * Ironically, or perhaps in a manner similar to Caitlin, who appears to have undergone a shift in personality with the death of Ronnie Raymond, Bette's surname means 'carefree' in French, the opposite of her repressed onscreen demeanor.