CHEROKEE — An explosion Tuesday that shook the Shoals blew the roof off the area of a nitrate plant where workers make ammonia, injuring one employee, but it appears the incident was contained, officials said.

The explosion at Cherokee Nitrogen was reported at 10:10 p.m., startling Cherokee residents and rattling homes throughout the Shoals. Officials said they heard reports of the blast being felt as far north as Tennessee and south as Tuscaloosa.

Mike Melton, director of the Colbert County Emergency Management Agency, said it appears no dangerous substances were released in the explosion.

“There was nothing on fire, nothing leaking after the event, so everything was contained to the facility,” Melton said. “It wasn’t a major issue off premises.”

The explosion did not result in a fire at the plant and crews soon accounted for all employees. The injured employee was taken to Helen Keller Hospital in Sheffield. His identity and condition were unavailable.

Melton said the report he heard is that the injuries are minor.

He said plant officials issued reports to the Alabama Department of Environmental Management and Environmental Protection Agency.

“To the best of my knowledge it was only residue that exploded,” he said. “Nothing leaked or anything like that.”

He said his understanding is employees had been working on a piece of equipment. “When they started it back up, that’s when it exploded.”

Nancy Giles, who lives about five miles south of the plant, said her husband was once a plant manager at the nitrate plant. When they heard the explosion, she said, he immediately knew what had occurred.

“When we heard it, it scared us to death,” she said.

R.J. Lambert, who lives off U.S. 72 in Cherokee, said he was still awake and went outside when he heard the explosion. He said he could tell it came from the nitrate plant.

“It rattled the whole house,” he said Tuesday night as emergency crews were clearing the scene. “It rattled every house in Cherokee.”

According to the company website, in November 2000, El Dorado Nitrogen, of El Dorado, Ark., acquired the Cherokee manufacturing plant from LaRoche Industries. El Dorado Nitrogen is a subsidiary of LSB Industries, headquartered in Oklahoma City, Okla. The plant in Colbert County operates as Cherokee Nitrogen Division and produces ammonia, regular nitric acid, ammonium nitrate solution and prill, and other ammonia-related solutions. The plant also produces high purity ammonia for refrigeration and metallurgical applications.

Senior Staff Writer Tom Smith and City Editor Sherhonda Allen contributed to this report.