Crews were sent to the PMC Biogenix chemical plant in Memphis, TN Tuesday afternoon after an explosion occurred and a fire ignited in the facility, local news organizations reported.

About 100 firefighters responded to the Pope Street site after the blast was reported around 3:30 p.m., coverage by CBS News affiliate WREG said. Upon arrival, personnel encountered thick smoke and a large fire.

Several videos of the incident posted to Facebook show a massive plume of gray smoke above the plant.

A fire official told the Memphis Commercial Appeal that the blast is thought to have occurred as a fatty acid was being handled. One injured person was taken to an area hospital and three others received treatment on scene for non-life-threatening injuries.

PMC Biogenix manufactures a variety of specialty chemical products using renewable resources, according to its website, including fatty acids, methyl esters, metallic stearates, glycerol and sorbitol esters, glycerin, and fatty amides and bisamides.