CLARKSVILLE — One person suffered severe burns Tuesday in an explosion at a gunpowder distributor in rural Johnson County, authorities said.

Investigators from the Little Rock office of the federal Bureau of Alcohol, Tobacco, Firearms and Explosives were investigating to determine the cause of the blast, which blew a hole in the roof and tore out part of a wall at Black Powder Inc., a spokesman for the Johnson County Sheriff’s Department said.

The one person who was working inside the building at the time suffered severe burns and was flown by helicopter to a Little Rock hospital, Chief Deputy Jerry Dorney said. He said the injured worker had a Lamar address but authorities did not immediately release his name, pending notification of relatives.

The sheriff’s office said it received a call about an explosion at 8:20 a.m. Sheriff’s personnel responded, along with city and volunteer fire departments, which extinguished a fire at the scene, Dorney said.

No one answered the telephone at the business or at the home of owner Jerry Dean on Tuesday afternoon. A message on Black Powder Inc.’s answering machine said the firm would be closed Tuesday and Wednesday "due to a family emergency."

The ATF office in Little Rock referred questions about the blast to the agency’s regional office in New Orleans. Spokesman Austin Banks did not immediately return a call seeking comment Tuesday afternoon.