HAVERHILL — The U.S. Environmental Protection Agency said on Wednesday that it has fined Sunoco Inc. $400,000 for alleged clean-air violations at the company’s chemical plant in Haverhill.

In its consent and final order, the EPA said it had reached an agreement with the Philadelphia-based refiner on Sept. 11 for failing to comply with federal requirements for controlling leaks of hazardous air pollutants from equipment at the plant.

The EPA found the violations in a series of inspections at the plant between Feb. 28 and March 3, 2005.

A little more than four months later on July 26, 2005, the EPA cited the Scioto County facility in a 10-count report.

EPA’s regional office in Chicago had cited Sunoco for reporting a number of improper seals on equipment and for failing to repair five leaking valves in less than 15 days.

Sunoco’s Haverhill plant produces alpha-Methylstyrene, Bisphenol-A and Phenol – all of which are classified as producing air-borne pollutants.

All three chemicals can cause serious health defects including cancer and birth defects.

They may also cause harmful environmental and ecological effects. The chemicals are used in resins and epoxies that are used in items like plywood, appliance parts, automobile coatings and compact discs.

They had until Oct. 11 to pay the non-taxable civil penalty.

Sunoco has not been the only Green Township industry under the watchful eye of EPA regulators in recent months.

Earlier this year, the government agency cited the Haverhill North Coke Co. for violating sulfur dioxide emission limits generated from its coke batteries.

Excess emissions of sulfur dioxide can increase the amount of acid rain and with increasing the chances of respiratory illness, heart disease, lung damage and premature deaths.

That case has not been settled, according to the EPA.