Deep-water oil and gas drilling in U.S. waters will be subjected to full environmental reviews, Interior Secretary Ken Salazar said, ending blanket exemptions such as one granted to BP Plc before its Gulf of Mexico spill.

So-called categorical exclusions from the reviews required under the National Environmental Protection Act will be restricted to drilling projects that involve “limited environmental risk,” Salazar said today in a statement. The department is reconsidering its process for evaluating the environmental impacts of drilling.

The department gave BP a categorical exclusion in 2009 for its Macondo well in the Gulf, which blew out April 20. An estimated 4.9 million barrels of oil leaked before the spill was stopped on July 15, according to government scientists. BP’s exploration plan for the well called the prospect of a spill “unlikely.”

“In light of the increasing levels of complexity and risk, and the consequent potential environmental impacts associated with deep-water drilling, we are taking a fresh look at the NEPA process,” Salazar said in a statement. “Our decision-making must be fully informed by an understanding of the potential environmental consequences of federal actions permitting offshore oil and gas development.”