Two Maryland firms have become the first companies on the East Coast to trade pollution rights under a program the state hopes to use to attract new industries.

With the blessing of the state government, a cement company has agreed to clean up 1,200 pounds a day of the pollution produced at a neighboring slag plant in return for the right to churn out 1,000 pounds of polluting particles a day at a new cement plant.

Besides producing a net cleanup of 200 pounds of pollution a day, the deal allows a new $70 million plant producing some 65 jobs to be built in an area where air quality regulations would have prohibited it without the trade. "It helps everybody," said George Ferreri, chief of Maryland's air quality programs.

The plant in question belongs to Atlantic Cement Co. of Stanford, Conn. In November Maryland officials approved Atlantic's proposal to take care of the air pollution impediment by cleaning up pollution at the Maryland Slag Corp. plant near the Sparrows Point site where Atlantic Cement hopes to build. The plan still must receive approval from the regional office of the federal Environmental Protection Agency.

Basically Atlantic proposes to modify and install equipment that reduces pollution by wetting down particles that otherwise might float through the air. In addition, the company also will pay for a wetting agent used in the process.

Although Atlantic will not know the exact cost of the bargain it struck until it begins to get estimates from contractors, a company official guessed the total cost will be less than several thousand dollars.

"We feel fine about it. We think everyone benefitted," said Jerry Meusel, manager of business and product development for Atlantic. It means that the cement company may build an otherwise unobtainable plant in the Baltimore area.

The equipment Atlantic will pay for is "equipment that Maryland Slag somewhere down the road would probably have had to install at its own cost," said Meusel. Under the trade, Atlantic bears that cost.

Atlantic had designed the proposed new plant to meet lowest-achievable emission rates, a requirement in areas such as Sparrows Point which fall below federal clean-air standards. "You can't screw it down any tighter," said Meusel. Because the company was unable to reduce its emissions more than it had in its design, finding someone else's pollution to clean up was Atlantic's only chance to locate in the area because U.S. law prohibits additional pollution.

"It took some negotiating, because it was the first time it had been done in Maryland," and because Arundel Corp., Maryland Slag's parent company is a customer of Atlantic, Meusel said.

Air pollution rights trading is a recently launched and still largely untried method of using the marketplace to achieve the largest possible reductions in air pollution at the lowest costs. Only about a dozen trades along the lines of the Sparrows Point deal have been made, almost all of them in California.