Environmentalists are divided over changes by the N.C. House this week exempting from state control the toxic-air pollution sources that fall under federal standards.

The state program limits emissions of 97 toxic pollutants that can cause cancer, birth defects and respiratory ailments. Created in 1990, it predates federal standards that now regulate about two-thirds of the state’s toxic emissions.

The N.C. Division of Air Quality, which runs the program, does not object to the measure approved by the House on Tuesday. It’s now before a Senate committee.

Federal rules prescribe emissions-control technologies for the industries they regulate. The state takes a different approach, requiring new and expanding businesses to prove their emissions won’t hurt the health of neighbors.

The House bill allows the air-quality agency to still assert that power if reviews find “unacceptable risk to human health.” Those businesses would then have to show their emissions aren’t harmful.

Businesses not regulated by federal law would still fall under state control.

“We don’t think the bill would have a big impact on the program,” said Tom Mather, a spokesman for the air division.

Few businesses covered by federal rules have had to install extra pollution controls after the state’s health-based analyses, air-quality officials say.

Industries pushed for the legislation last year, saying the state program duplicates the federal standards and causes companies undue expense.

The Southern Environmental Law Center still opposes the bill, saying it erases the preventive aspects of the state’s health-based analyses.

“Once you remove that requirement in the permit, all that information available to the (air-quality) director is no longer required,” said Carolinas director Derb Carter. “Even though there will be a review of risks, the information on which to make that review is not going to be available.”

Twenty-seven companies and trade associations that would benefit from the bill spent $8.9 million to lobby state officials and support their political campaigns, the watchdog group Democracy North Carolina reported Thursday.

The analysis cited nearly $1.2 million spent by Duke Energy, which pushed for passage of the bill last year. The bill passed by the House removes an exemption for industries like Duke that burn fossil fuels. Federal rules for utilities were released last December.

The Sierra Club says the bill is improved from last year’s broadly worded version, said state director Molly Diggins, and reflects some of the changes environmental groups had recommended. The club has not taken a position on the bill.

Gov. Bev Perdue supported this year’s version of the bill.