Los Angeles (CNN) -- People living downwind of the Port of Los Angeles were warned to stay indoors because of potentially toxic smoke from a wharf fire Tuesday morning.
A hundred firefighters, using boats, trucks, helicopters and scuba gear, extinguished the blaze Monday night, but the Los Angeles Police Department issued a smoke hazard alert early Tuesday.
"If you are in the Port of Los Angeles area, please shelter in place," the alert said. "This means stay indoors. Bring your pets inside if possible. Close your doors and windows. Turn off air conditioning."
The four-alarm fire burned about 150 feet of a wooden dock that stretched under a warehouse and threatened nearby cargo ships, Los Angeles Fire Department spokeswoman Katherine Main said.
The warehouse did not catch fire, but heavy timbers under it burned, she said.
The Port of Los Angeles, about 20 miles south of downtown Los Angeles, is the busiest container port in the United States and ranks 16th in the world, according to the American Association of Port Authorities.
CNN's Artemis Moshtaghian contributed to this report.