LOS ANGELES (AP) — Dozens of firefighters were battling a blaze on a container ship docked at a Los Angeles port on Friday night, according to officials.

All of the 23 crew members were accounted for and there were no injuries from the electrical fire, which appears to have started below deck, according to the Los Angeles Fire Department. The ship's cargo includes hazardous materials.

By about 7 p.m., the fire had spread to several levels of the ship, according to the fire department, and later an explosion took place mid-deck. It was not immediately clear how the fire started.

More than 100 firefighters were fighting the fire at the Port of Los Angeles, according to Los Angeles Mayor Karen Bass. The port is known as the busiest in North America.

“LAFD Hazardous Materials companies are monitoring air quality as fire suppression continues,” she said.

The 1,102-foot-long (336-meter-long) vessel, the One Henry Hudson, is operated by One Ocean Express, a shipping company headquartered in Singapore. Before Los Angeles, the ship had most recently been in Japan, stopping in Kobe, Nagoya and Tokyo. One Ocean Express did not immediately respond to an email from The Associated Press requesting comment.