Crews clean shipping container debris that washes ashore at San Francisco beach

Coast Guard officials are urging mariners to be cautious as they navigate the waters near the San Francisco Bay and to be on the lookout for a dozen containers that were thrown off a cargo ship just outside the Golden Gate Bridge.

A container filled with plastic pallets broke apart and washed up on San Francisco's Baker Beach, where on Monday crews were working to clean the debris out of the area.

The Coast Guards says 12 containers, most of them empty, were washed overboard of a cargo ship Friday because of stormy seas.

The Coast Guard says a few were loaded with various kinds of packing material and that none of the materials are hazardous to marine life.

It says the ship's owner hired an environmental contractor to track down the containers and clean up any debris that washes ashore.