The US Environmental Protection Agency (EPA) will slow the phase-in of new limits on carbon dioxide from coal and other heavy industry plants, it has been announced.

In September 2009, the EPA asked the coal plants, refineries and other heavy industry facilities emitting over 25,000 tons a year of greenhouse gases to obtain permits that show they are using the best technology to reduce emissions.

In a recent letter to senators, the EPA said the facilities will not require the permit under the Clean Air Act before 2011.

The agency also plans to increase the emission threshold, beyond which permits are required to reflect public consultation.

The EPA said it does not intend to place smaller plants under the permit regime before 2016, according to the letter, reports Reuters.