The Associated Press

COLUMBUS - A U.S. Environmental Protection Agency pollution investigation of asphalt companies, which mix crude oil and gravel to make road-building materials, has expanded from Ohio to other states.

The agency has ordered pollution tests and company records from two asphalt plants in Illinois and one each in Indiana, Michigan, Minnesota and in Fairborn, Ohio, near Dayton, The Columbus Dispatch reported Monday. Two Columbus asphalt companies got similar orders earlier in the year.

While the agency hasn't discussed the investigation publicly, the EPA said earlier that demands for internal records are the first official steps taken when it suspects Clean Air Act violations.

Ohio has more than 300 asphalt plants. There are more than 1,100 asphalt companies nationwide, many with several operating plants.

Plant owners and the industry's trade association said they didn't know the reason for the EPA directives and questioned the cost.

"I'm one of 200 or so plants in Illinois," said Stephen Kennedy, vice president of Rock Road Cos., which runs a plant in Rockford. "I'm wondering why I'm doing this and my competitors are not."

Bill Omohundro, an EPA spokesman, would not comment about the expanded investigation, the newspaper said. Omohundro could not be reached for comment Monday, which was a federal holiday. A message was left at his Chicago office.

The letters sought new air-emission tests for soot, carbon monoxide, nitrogen oxides, sulfur dioxide and volatile organic compounds. Companies must provide information about modifiers put into liquid asphalt and about the fuel burned to keep asphalt from hardening.

Alvin Evans, chief operating officer for J.H. Rudolph & Co. Inc. in Evansville, Ind., said he was asked to test for things the state doesn't require. He said Indiana requires estimates of volatile organic chemicals, nitrogen oxides and sulfur emissions. "We've asked for an extension of the time period we've been given," Evans said.

The other companies facing directives from the EPA were Central Specialties Inc. of Alexandria, Minn.; Ajax Materials Corp. of Warren, Mich.; Barrett Paving Materials Inc. of Fairborn; and Chester Bross Construction of Loraine, Ill., the newspaper said. None could be reached for comment Monday.

Gary Fore, vice president of environment and safety for the National Asphalt Pavement Association, called the letters unprecedented and said his group would discuss them with the EPA. Fore said the industry has worked for 10 years with the EPA on studies that show asphalt plants are not major sources of pollution.

Theresa Mills, director of the Buckeye Environmental Network, and Simona Vaclavikova, a program director for Ohio Citizen Action, say the tests might not cover all the hazardous substances asphalt plants emit into the air.

Both said neighbors began to complain about asphalt plants in Ohio around 2000. Mills suspects complaints might be linked to the used oil some plants burn as fuel or new modifiers put in the asphalt.

The industry-supported Asphalt Institute said asphalt is the environmental choice of highway builders because, in part, it can be colored to match the surrounding environment and, without seams like concrete sections, can be quieter amid heavy truck traffic.