HAVERHILL — The Haverhill North Coke Co. is seeking approval from the Ohio Environmental Protection Agency to modify its air permit.

If passed, the permit would allow the company to reduce its number of coke ovens from 400 to 200.

The company is also seeking permission to increase the sulfur content in the coal used to produce coke — high sulfur coal is more plentiful — and include emission limits and control for mercury, something that was not included in the original permit.

“We are still going to be a low-emission facility,” plant spokesman Gerald Davis said. “The Haverhill North Coke Co. uses the only proven heat recovery technology in the world. It is a low-emission facility, and it will continue to be.”

The proposed modifications also would reduce the number of days the plant could bypass emission control equipment during maintenance. Currently, the permit allows 14 days of emission control bypass; the proposal would cut that figure to eight.

In December 2003 a permit was issued by the EPA for two-phase construction. During the first phase, 100 ovens were built. The second phase called for an additional 300, according to Davis.

Phase I was completed, but plans for phase II are being modified to reflect customer requests, Davis said.

A public hearing on the request was conducted last week at Green High School. Monday was the last day to submit written comments to the EPA’s Portsmouth Local Air Agency. A decision on the request will come early this summer.

“It will probably take two weeks to get a transcript of the informational meeting. It may take three to four weeks before a final decision is made whether to grant the request,” said Cindy Charles, of the Portsmouth Air Agency. “The decision will be made on the technical merits of the request.”

The Haverhill facility is owned by Sun Coke Co., a subsidiary of Sunoco, Inc.

The $157-million, 100-oven plant in eastern Scioto County began operations in March and now produces 550,000 tons of coke each year for the steel industry. It employs 65 people.