(Photo: AP)

NEW ORLEANS — Forensic testing of a key piece of evidence in the Gulf oil spill investigation could take twice as long as expected.

An investigator with the U.S. Chemical Safety Board – one of the groups monitoring the testing – said Friday his agency has been advised the examination may not finish until March 20.

The Interior Department had said testing of the 300-ton blowout preventer that failed to stop oil from spewing into the Gulf of Mexico following last year’s rig explosion would take two months once it started Nov. 16.

That timeframe passed on Sunday. (READ MORE)