Crews are working around the clock to clean up a chemical spill at the Fryburg Rail Terminal that people reported smelling 30 miles away in Dickinson.
Andeavor Logistics reported a spill on Sunday of ethyl mercaptan, a liquid with a strong odor that is added to propane to allow the public to detect gas leaks.
“It’s a noxious, nasty odor,” said Ron Day, spokesman for Marathon Petroleum, which owns Andeavor Logistics.
The North Dakota Department of Health said it is closely monitoring the spill and working with local emergency responders.
An independent contractor is monitoring the air surrounding the facility and results show low concentrations of ethyl mercaptan, according to the health department.
Health officials advise people with respiratory conditions or other sensitivities to minimize exposure, but said the concentrations do not warrant a general health advisory.
“You’re going to be able to smell it, but we have not seen any detectable levels in any community outside the perimeter of the facility,” Day said.
An estimated 200 gallons to 600 gallons were released due to a tank leak, Day said. The liquid spilled from a 1,400-gallon tank that was not full at the time.
Crews stopped the leak and emptied the tank into sealed drums, Day said. The spilled ethyl mercaptan stayed within a metal containment unit around the tank that is not covered.
The liquid is highly flammable, which slowed the response to the incident, Day said.
Crews are adding household bleach to the ethyl mercaptan to neutralize it and then adding an absorbent material, he said. They will use shovels to remove it and haul it to a special waste landfill.
The work is expected to continue 24 hours a day. Health department personnel are monitoring the cleanup.
Day said people in Dickinson reported smelling the spill Monday night, but conditions improved on Tuesday. The rail terminal is about 1.5 miles away from the boundary of Theodore Roosevelt National Park.
“We’re definitely apologetic to the community,” Day said. “We’re responding as fast and as furious as we can.”