A South Carolina woman driving to work was killed by an ammonia leak from a chemical plant that sent a deadly cloud across a rural highway, authorities said.

Jacqueline Ginyard's body was found next to her car on U.S. 321, The (Columbia, S.C.) State reported. Police said they believe the ammonia caused Ginyard's car to stall and she was overcome by the fumes as she tried to walk out of the chemical cloud.

A firefighter, Curtis Smith, appears to have saved other lives. Smith smelled ammonia as he drove to work at the state Department of Health and Environmental Control in Columbia and saw what looked like smoke coming from the Tanner Industries plant.

Smith used his truck to improvise a roadblock, halting traffic on the highway.

"As a fireman, I knew you couldn't drive through ammonia," he said.

Ginyard's daughter, Marva, 16, along with her minister and friends, spent hours looking for her mother Wednesday, the newspaper said.

Marva got a call at her home in Wagener that morning asking why her mother had not arrived at her job as a home health aide.