LOS ANGELES (AP) — A fire that broke out aboard a Los Angeles container ship on Friday continued to burn overnight, prompting a shelter in place order for surrounding communities over concerns about hazardous materials within the ship’s cargo.

All 23 crew members of the ship were accounted for and there were no injuries from the electrical fire, according to the Los Angeles Fire Department. Officials said they had identified hazardous materials aboard the vessel, the One Henry Hudson.

Just before 3 a.m., Mayor Karen Bass announced a shelter-in-place order for the areas around the port, including San Pedro and Wilmington. Mayor Bass urged residents to “remain at home, keep windows closed and turn off HVAC systems.”

The U.S. Coast Guard said a safety zone of one nautical mile had been established around the vessel.

The fire appears to have started below deck before spreading to several levels of the ship, leading to an explosion mid-deck. The cause of the fire is still not clear.

More than 100 firefighters responded to battle the blaze at the Port of Los Angeles, known as the busiest seaport in North America. Their efforts continued overnight, actively working to bring the situation under control.

The ship, operated by One Ocean Express from Singapore, had most recently traveled through Japan, making stops in Kobe, Nagoya, and Tokyo before arriving in Los Angeles.