A section of Congress Street on Munjoy Hill was closed Wednesday morning because of a chemical spill from a truck carrying insulation material.

Portland Assistant Fire Chief Keith Gautreau said a Portland police officer spotted liquid leaking out of the rear of an Anderson Insulation truck on Congress Street as it headed up Munjoy Hill around 7:30 a.m.. The truck was stopped by police at the top of the hill, in front of the Munjoy Hill fire station.

Gautreau said the liquid is a polymer that is mixed with another chemical to create blow-in foam insulation.

He said it’s considered hazardous in unventilated spaces and can cause a chemical burn if it comes into contact with skin and if water is then applied. It is also flammable, but is not considered highly flammable, he said.

As of late Wednesday morning, Gautreau said there were no reports of anyone coming in contact with the liquid.

Crews from the fire department and the Maine Department of Environmental Protection applied an absorbent material to the spill in front of the fire station. There was some liquid spilled on the way up Congress Street, Gautreau said, but the company that owns the truck said it would dry and evaporate rapidly.

Gautreau said the spill occurred when a 55-gallon drum in the back of the truck tipped and overturned. The drum was about half-full, he said,

Gautreau said it wasn’t clear why the drum tipped. Other material in the rear of the truck was either chained or strapped in place, he said, but it wasn’t clear if the drum had been secured or if a chain or strap holding the drum had broken.

The company was cited for failing to prevent its cargo from shifting, said Cpl. Chris Rogers of the Maine State Police.

Anderson Insulation is based in Abington, Massachusetts, Rogers said, but operates a warehouse in Saco where material for jobs in Maine is stored. The truck had a Maine commercial license plate.

DEP workers and firefighters bagged up the absorbent material that had been spread on the road and then a firefighter in a hazmat suit got into the rear of the truck, put the drum upright and began spreading bags of the absorbent material inside the truck.

Gautreau said the company was arranging to take the truck to a facility where it could be decontaminated and cleaned.

Police reopened part of the street around 10 a.m.

A search of Occupational Safety and Health Administration records indicated that Anderson Insulation was cited twice in 2014 and once in 2013 for violations at its Massachusetts location, but those violations did not appear to be related to the transportation of chemicals.

The Maine DEP said Wednesday afternoon that its records indicated the company has not had any prior environmental issues in Maine.

Correction: This story was updated at 11:45 a.m. on May 17 to correct the time that the street was reopened.