Officials say an explosion at the Blacklidge Emulsions plant in Gulfport is still under investigation.

No one was injured when a 40,000-gallon asphalt tank exploded around 6:15 p.m. Friday at the plant. Firefighters battled huge flames for more than two hours.

By 8:30 p.m., firefighters and an airport crash truck from the Air National Guard Base alternated spraying water on tanks.

The Mississippi Department of Environmental Quality, Mississippi Power Company, American Medical Response, Harrison County Emergency Management and Gulfport police were at the scene.

Brooke Shoultz, a spokeswoman for Blacklidge, said only a few workers were at the plant when the tank exploded. Blacklidge Emulsions makes asphalt emulsions, binders, seal coats and specialty asphalt emulsions for the road paving industry.