Updated

The Obama administration this weekend released the first major part if its second-term regulatory agenda, an initiative costing as much as $350 million targeting fossil-burning boilers and incinerators that critics says hits companies already struggling in a tough economy.

The Environmental Protection Agency regulations released late Friday attempt to improve Americans’ health by reducing soot from the industrial boilers and incinerators.

The agency estimates the cost of implementing the new standards will cost  $53 million to $350 million.

Republicans have opposed the environmental regulations as detrimental to business during tough economic times and failed to slow down the new rules in Congress.

In addition, industry groups said the regulations on industrial air pollution are still overly burdensome.

Jay Timmons, president and chief executive officer of the National Association of Manufacturers, said the rules were "far from being realistic" and accused the EPA of pushing "another costly and crippling regulation at a time when our economy is on the brink."

The EPA said the court-order changes offer more flexibility and lower costs than earlier proposals to comply with the new standards.

The agency also said it cut the cost of compliance by about $1.5 billion.

Obama administration officials said most of the 1.5 million boilers nationwide are not covered by the regulation since they are too small or emit too little pollution to warrant controls.

The changes will require pollution controls at about 2,300 of the largest and most polluting boilers nationwide, including those found at refineries and chemical plants. Those boilers will have three years to comply and could be granted a fourth year if they need to install pollution controls.

Another 197,000 smaller boilers would be able to meet the rule through routine tune-ups.

Environmental groups said the rules were not as stringent as they had hoped but would help Americans breathe cleaner air.

"These standards are a mixed bag," said John Walke, director of the Natural Resources Defense Council's Clean Air Program.

The EPA estimated the scale-back standards will still provide significant health benefits – including the prevention of as many as 8,100 premature deaths, 5,100 heart attacks and 52,000 asthma attacks.

“These standards are fulfilling the promise of the Clean Air Act,” said EPA Administrator Lisa P. Jackson. “We will save lives and reduce the burden of illness in our communities, and families across the country will benefit from the simple fact of being able to breathe cleaner air.”

Industrial boilers burn coal and other fuels to generate steam and hot water for heat and electricity. After coal-fired power plants, boilers are the nation's second-largest source of mercury emissions, a potent neurotoxin. But boilers are among a handful of pollution sources that still have no standards for toxic emissions.

Fine particle pollution can penetrate deep into the lungs and has been linked to a wide range of serious health effects, including premature death, heart attacks, and strokes.

A federal court ruling required EPA to update the standard based on best available science.

The Associated Press contributed to this report.