About 500 residents evacuated their homes after a train carrying sodium cyanide rear-ended a second train and caught fire, authorities said. No injuries were reported.

The collision Wednesday evening in north Alabama sent flames and a plume of black smoke into the air that could be seen 40 miles away in Birmingham, officials said. The blaze continued late into the night.

Susan Terpay, spokeswoman for Norfolk Southern, which operates both trains, said it did not appear that the train car carrying the chemicals had been breached. Both trains were en route to Atlanta, she said.

Terpay said the first train was carrying automobiles and had pulled off into a siding along the main tracks to let the second train pass, but not all of the 81 cars cleared the tracks.

Talladega County EMA spokeswoman Shay Cook said residents within one mile of the site were asked to evacuate as a precaution.

Deborah Gaither, deputy director of the Talladega County Emergency Management Agency, said air monitoring in the Lomar Ville area — where about 20 to 30 residents were blocked in by the trains — had been completed and no chemicals were detected in the air there.