The names of three men injured Wednesday in a sulfur explosion at Northeast Agricultural Sales Inc. in Detroit, where they work, have been released by the state Fire Marshal’s Office.

Anthony Towers, 62, of Newport, is being treated for extensive burns at Maine Medical Center in Portland, according to Steve McCausland, spokesman for the state Department of Public Safety. Lee Gustin, 50, of Cambridge, and Clarence Rider, 36, of Pittsfield, were treated at Sebasticook Valley Hospital in Pittsfield after complaining of respiratory problems, according to a release from McCausland.

A spokeswoman at Maine Medical Center said Thursday afternoon that the hospital has no information on a patient with the name Anthony Towers.

Fire investigators said the explosion took place in an empty 86-foot-tall silo used to store sulfur, and Towers and Rider were working on top of the silo, according to McCausland. Towers was cleaning out accumulations of dust and sulfur with a shovel when a spark set off the explosion, which caused his clothing to catch fire. Rider put out the fire before both men climbed down a ladder to the ground. Gustin, who was working on the ground, came to assist the two men after they climbed down, the release said. A Lifeflight helicopter flew Towers to Portland, according to McCausland.

Investigators are continuing to work on what caused the spark at the company,which sells farm equipment and is located off Route 100 in Detroit, a small town in Somerset County.

A woman who answered the phone at Northeast Agricultural Sales early Thursday afternoon said company owner Justin Chouiniere was unavailable for comment.

Pittsfield Fire Chief Bernard Williams, who was at the scene Wednesday, said the explosion was caused when a spark ignited sulfur dust that exploded.

Firefighters from Pittsfield, Corinna, Newport, Detroit, Skowhegan and Plymouth went to the scene, as did officials from the Maine Department of Environmental Protection, the Somerset County Sheriff’s Office and Maine State Police.

A call placed to the state fire marshal’s office Thursday was not returned.

There was no visible sign of damage at the scene, and everything seemed to be intact there, according to Williams. The fire was contained to the binlike container where products are mixed before being dropped into trucks.

Emergency officials responded to the report of the explosion just before 2 p.m. Wednesday.

Amy Calder — 861-9247

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Twitter: @AmyCalder17