Jessi Combs, a professional speed racer and former host of Mythbustersdied Tuesday in a crash on the Alvord Desert in Oregon as she was in a jet car attempting to break a land-speed record. She was 39.

The Harney County Sheriff’s Office was called to the scene of the fatal crash in the desert about 90 miles south of Burns, Oregon, around 4 p.m. on Tuesday. Combs was identified as the driver and the sole fatality connected with the accident, which is under investigation. Terry Madden, a member of Combs’ team, said she died “in a horrific accident,” that he “was the first one there” and “did everything humanly possible to save her.”

Mythbusters host Adam Savage tweeted, “She was a brilliant … builder, engineer, driver, fabricator, and science communicator, & strove everyday to encourage others by her prodigious example.” Combs also appeared on Break RoomOverhaulin‘ and All Girls Garage.

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