Oil and gas companies wouldn’t be required to disclose chemicals used in hydraulic fracturing until work is completed, under a proposed federal rule issued today that drew swift opposition from environmental groups.

The proposal would add about $11,833 in costs per well in 2013, according to the rules released by the Interior Department.

“This administration’s energy strategy is an all-out effort to boost American production of every available source of energy,” Interior Secretary Ken Salazar said in a statement.

President Barack Obama has pledged to increase U.S. natural gas production in a way that doesn’t hurt the environment. Hydraulic fracturing, or fracking, releases gas trapped in shale rock by injecting water, sand and chemicals thousands of feet underground. It’s used for almost every new natural-gas well drilled on U.S. land.

While environmental groups had preferred an earlier version of the standards that would have required disclosure before the work began, the industry argued for reporting after the work was completed.

“This is a free pass to the oil and gas industry at the expense of public health,” Jessica Ennis, a Washington-based legislative associate for the environmental group Earthjustice, said today in an e-mail.

The Washington-based American Exploration and Production Council, representing natural gas companies including Anadarko Petroleum Corp. and Apache Corp., had said more disclosure will slow energy development. The Independent Petroleum Association of America called the rule “an unnecessary layer of rigidity” in an e-mail sent after the rule was released.

Fracking, used by companies such as Exxon Mobil Corp and Chevron Corp., helped the U.S. become the world’s largest natural gas producer. While Interior rules would only apply to the federal lands, the administration hopes states will follow their model.