ANCHORAGE, Alaska - Alaska cleanup crews last year found some beaches covered with polystyrene foam that floated across the Pacific from the 2011 Japanese tsunami and threatens wildlife, a state official told legislators on Tuesday.

A main concern of environmentalists and officials is that the lightweight specks, which have been broken down by storms and waves, will harm small animals. They could choke or die slowly from malnutrition if pieces block their intestinal system, officials say.

So far, no dead birds have been found on the beaches, Elaine Busse Floyd, acting environmental health director for the Alaska Department of Environmental Conservation, told lawmakers in her report. But officials are on the lookout for animals harmed by the ingested foam, she said.

Polystyrene foam accounted for 30 percent of the weight of the total debris, compared to the usual 5 percent rate before the tsunami, she said. Considering that it is so light, "it's a huge volume."

Closed-cell extruded polystyrene is often referred to as Styrofoam, a trademarked name owned by Dow Chemical Co., which manufactures it for insulation and crafts, among other uses. It is not biodegradable because it resists breaking down in sunlight, so it can in theory last forever.

Scattered bits of foam are difficult to retrieve from the environment and are easily mistaken by animals for morsels of food, Floyd told a legislative committee in Juneau.

Animals are already munching on tsunami polystyrene foam, said Chris Pallister, president of the nonprofit Gulf of Alaska Keeper which conducted most of last year's beach cleanups.

"We have personally seen plenty of animals eating it, pecking at it, playing with it," Pallister said.

Cleanup crews have spotted foam bits in scat from bears and other animals, he said. "The question is, are animals metabolizing that or is it breaking down and being released into the environment?"

Pallister's group worked from May to October to clean up about 300 miles (483 km) of beaches in outlying coastal areas. Other groups conducted more short-term cleanup projects.

Already, Gulf of Alaska Keeper is preparing for next summer's cleanup. "It's a pretty amazing sight when you go out to the coast and see nothing but Styrofoam as far as you can see," he said.

The material that has washed ashore in Alaska from the 2011 tsunami in Japan includes foam buoys and insulation ripped from people's homes, officials said.

Debris from the tsunami has also washed ashore in other U.S. states on the Pacific Ocean, including in Washington and Oregon where a Japanese dock turned up on the coast.

But the problem is particularly acute in Alaska because it has a longer coastline than other states, and many beaches are remote which makes cleanup difficult and expensive, Floyd said.