Published: May 27, 2010 9:21 PM EDT
Updated: May 27, 2010 6:22 PM EDT

WASHINGTON (AP) - Interior Secretary Ken Salazar says the government will require certification of emergency cutoff valves on offshore oil wells like those that failed in the massive oil spill in the Gulf of Mexico.

Salazar said Thursday he will propose rules requiring certification of so-called blowout preventers by an independent third party, as part of an effort to tighten oversight of offshore drilling.

After the April 20 explosion and oil spill, Salazar ordered immediate inspections of all 33 deepwater drilling rigs in the Gulf.

Inspectors checked if blowout preventers had been tested and if emergency exercises were taking place. The machinery weigh up to 640,000 pounds and are supposed to stop uncontrolled blowouts in exploratory wells.