Several explosions and a fire involving tons of liquid asphalt were reported at the Gardner Fields asphalt plant in Tacoma, WA on Sunday morning, leading officials to issue a smoke advisory to those living near the facility.

The blaze is thought to have ignited after a supply lines to two silos failed, Tacoma Fire Department Assistant Chief Alex Wilsie said in an interview with The Tacoma News Tribune. The exact cause of the incident is unknown. One of the two silos contained about 70 tn of liquid asphalt when the fire broke out.

Crews were sent to the asphalt plant at about 4:30 a.m. A HAZMAT team and officials from the state’s Department of Ecology and Tacoma Environmental Services were also dispatched to the site, according to NBC News affiliate KING.

Because the thick smoke coming from the fire possibly contained toxic substances, fire officials issued a smoke advisory and told residents near the plant to remain indoors for several hours, the television news station said.

No injuries were logged during the incident, coverage by news broadcaster KIRO said.