Gary Foersch visited the byproducts area at Tonawanda Coke at least 15 times during his career as a state inspector.

Despite those numerous visits, Foersch never noticed a bleeder valve that is believed to be a major source of air pollution and is at the crux of the government’s criminal prosecution of the Town of Tonawanda manufacturer.

Foersch, a retired inspector at the state Department of Environmental Conservation, was the first witness called by Tonawanda Coke and fellow defendant Mark F. Kamholz, the company’s environmental controls manager, as part a defense that suggests the company complied with clean air regulations until inspectors suddenly changed the rules.

“Do you know what that is?” Defense attorney Rodney O. Personius asked Foersch while showing him a photo of the bleeder valve in court Wednesday.

“No,” said Foersch.

“You never noticed that pipe?” Personius asked.

“No,” said Foersch.

“Can we agree it looks like an emission point?” Personius asked.

“Yes,” said Foersch.

Foersch said it’s possible he overlooked the bleeder, or pressure-relief valve, because he always focused on other aspects of the plant during his inspections.

The valve and its emissions – the allegation is that it spews toxic coke oven gas – have become a focal point of the criminal case against Tonawanda Coke and Kamholz, and the defense has responded by asking why state inspectors went years, even decades, without noticing it.

Company employees, both current and former, have testified that the valve opened every 20 to 30 minutes to release pressure from the plant’s coke oven gas line.

Prosecutors say the gas that came from the valve included benzene, which is why the valve is at the heart of six of the 19 charges against the company and Kamholz.

The prosecution of Tonawanda Coke comes at a time when residents surrounding the River Road plant are increasingly concerned about their health and air quality.

A recent study by the state found elevated levels of certain cancers and birth defects among those residents, though officials have stopped short of identifying a cause.

An earlier study also found concentrations of benzene and formaldehyde to be much higher in the Tonawanda area than in other industrial and urban areas.

Foersch, a state inspector for nearly 40 years, also testified about the need for baffles, a piece of anti-pollution equipment, on two “quench towers” at Tonawanda Coke.

The criminal charges against the company include 10 separate allegations that Tonawanda Coke’s two towers, which are used to cool the hot coke produced at the plant, were not equipped with baffles.

Personius asked Foersch if he was aware that the company had an exemption for one of the towers, and referred to a 1984 DEC letter citing its infrequent use.

“The installation of baffles is not required due to unreasonable cost and physical impairments,” the DEC said in the letter.

Despite that letter, the criminal charges include allegations that neither tower had baffles.

Foersch said he advised Kamholz to install baffles in the second tower but added that he doubted Kamholz ever followed through. And yet, he never cited the company for not having baffles in the second tower.

“Isn’t it true you knew, in your heart of hearts, that there were no baffles in Quench Tower No. 2?” Personius asked.

“I had a gut feeling there weren’t baffles in there,” Foersch said.

The trial before Chief U.S. District Judge William M. Skretny resumes today.