RALEIGH — Jobs or toxic air pollution. The either-or choice isn't quite that stark, but the North Carolina General Assembly is closing in on cutting back a clean-air law that supporters credit with cutting two-thirds of the nasty airborne chemicals over a decade.

Legislation that passed the House last week would pare back state regulation of toxic industrial chemicals like ammonia and sulfuric acid released into the air. A Senate vote hasn't been scheduled.

The state airborne toxics law allows regulators to consider the health risks to a community near a polluting plant, while federal rules set a pollution standard that varies depending on the industry. Generally, companies subject to the federal requirements meet them if they use the best available technology for their emissions.

The legislative change would affect less than 10 percent of the 2,700 plants with air quality permits that are subject to both state and federal toxic rules, according to data compiled last year. Exemptions from the state program would primarily go to power plants, paper mills and chemical manufacturers.

Despite that, the jobs-versus-environment dichotomy has made the issue of whether to pull back on state regulations one of the most partisan and most animated in this year's legislative session.

Big polluters last year asked lawmakers to scrap the state air regulations and leave the federal rules. Requests came from steelmaker Nucor Corp.; Domtar, which operates a paper plant in coastal Washington County; and Duke Energy, which operates several coal-fired power plants in western North Carolina. They were responding to Republicans, who last year took over control of the General Assembly for the first time in more than a century and invited businesses to point out state regulations that companies said were limiting their ability to create jobs and profits.

"This bill is simply about jobs," N.C. Rep. Mike Stone, R-Lee, said before the House voted last week. "Let's go ahead and pass this bill and get rid of more regulation."

House Minority Leader Joe Hackney, D-Orange, derided the prevailing argument that the state's air toxics law and federal regulations duplicate each other.

"That has never been true," Hackney said, "because the federal standards are technology-based — which is, this is the technology you must use — and not health-based — which is, you go to the property line or over into the next neighborhood and find out how much of the stuff is coming down on the kids in the neighborhood. Those are not the same thing."

Democratic Gov. Beverly Perdue's administration is going along with the changes, in part because the proposed legislation includes language allowing state environmental regulators to step in if a plant's pollution poses an "unacceptable" health risk.

Companies subject to the federal standards will still have to report their air emissions to show they're complying, and the Department of Environment and Natural Resources will check to see if more research into the potential human impact of toxic chemicals is warranted, the agency said.

"I guess there's some scenario that the division can perform its own investigation, analysis, modeling," said Derb Carter, director of the Carolinas office of the Southern Environmental Law Center. But after a 15 percent funding cut last year on top of previous years of cutbacks, "they barely have enough staff to issue permits let alone conduct those sorts of investigations."

North Carolina adopted its air toxic regulations in 1990 during the administration of Gov. James Martin, a Republican. The U.S. Environmental Protection Agency didn't regulate the pollutants then. Most other states adopted air toxic programs during the 1990s, but many have dropped or minimized them since.

North Carolina now has the tenth-highest level of toxic air pollution in the country, and the fourth-highest level from chemical companies, DENR said.

Manufacturers and chemical companies say reducing North Carolina's oversight for industries subject to EPA limits levels the playing field with neighboring Southeast states. Companies are often concerned with how quickly they can get new products to the market, and they can do it faster in states fewer air regulations, said Preston Howard, president of the Manufacturers & Chemical Industry Council of North Carolina.

"As a result, North Carolina is losing that production and the jobs that go along with it," Howard said.