North Dakota firefighters continued to battle a huge blaze at an oil industry supply business in the town of Williston that spewed 500-foot-tall flames, officials said Tuesday.
Explosions and flames began shortly after midnight Monday at Red River Supply, the Williams County Emergency Services told the Los Angeles Times. A state highway near the fire was closed.
A half-mile radius around the fire has been evacuated, but no injuries had been reported. Emergency officials said in a Tuesday afternoon statement that they did not think they would have to increase the evacuation area.
The cause of the blaze was under investigation.
Red River Supply is a family-owned and -operated company that offers various products and services to the local oil industry. Founded by Rich Vestal in the 1970s, the company distributes rail spurs for loading and unloading crude oil, drill pipes and casing. It also provides storage, blending and delivery of drilling fluids -- such as calcium chloride, calcium bromide, calcium nitrate and potash -- according to the company's website.
Vestal was out of town when the fire began.
"For now, all I know is that it's burning up a bunch of my trucks and one of my fields," he told The Times on Tuesday morning.
Fire departments from three counties, the North Dakota hazardous materials response team and the North Dakota National Guard were called in to battle the blaze, which has been mostly contained. But emergency officials said they would stay on the scene for 24 to 48 hours.
The site continued to spew plumes of black smoke that "may adversely affect air quality in the surrounding area and may cause health concerns," the North Dakota Health Department said in a statement.
The department said it was monitoring air and water quality. Preliminary results of the air sampling did not show any toxic materials in the smoke plume, the department said, but testing was to continue. People with respiratory conditions should stay indoors and keep their windows closed, the department said.
There was a temporary flight restriction at Sloulin Field International Airport on Tuesday morning because of the potentially hazardous smoke, but the airport later reopened, according to its website.