Days after a warning from activists on the Gulf of Mexico, Plains All American says it continues collecting oiled animals and soil from California beaches.

Plains said May 19 it was aware that as much as 2,500 barrels of oil was released from its Line 901 in Santa Barbara. About 500 barrels may have reached the waters off the coast of Refugio State Beach in a release the Environmental Protection Agency said was the worst spill in California in the last 25 years.

The company said Monday more than 14,000 cubic feet of oiled sand was removed from California beaches so far. No visible sheen remains off the California coast. A total of 11,915 gallons, the equivalent of 283 barrels, of an oily-water mixture have been recovered to date.

In terms of wildlife, the company said 50 birds and 30 mammals were recovered dead during the incident response.

"Capture and recovery teams continue to rescue wildlife affected by the incident," the company said. "The public should not attempt to rescue oiled wildlife."

The Louisiana Environmental Action Network warned last week of the residual threats from the 2010 oil spill in the Gulf of Mexico.

"We see daily pictures of citizens [in California] wearing sandals, shorts and t-shirts rescuing birds and cleaning beaches," the group said in an open letter. "This is an absolutely unacceptable manner of dealing with these materials and needs to be ceased immediately."

Two state beaches, including Refugio, remain closed. A unified command overseeing the response said a safety zone is in place around cleanup operations.

The company said it wasn't issuing comments on the status of the pipeline until the investigation process is complete.