Following a six-day inspection in 2009, Tonawanda Coke told federal officials that toxic emissions from a small bleeder valve at the plant were rare and didn’t last long when they did occur.

For the first time Friday, an official with the U.S. Environmental Protection Agency challenged those claims in Buffalo federal court and suggested the amount and frequency of the emissions were substantially higher than what the company claimed.

The valve’s emissions – the allegation is that it’s coke oven gas with benzene – are at the crux of the government’s clean air and obstruction of justice charges and account for six of the 19 felony counts facing Tonawanda Coke.

“I would not consider that de minimis,” Harish Patel, an EPA environmental engineer, said of the government’s estimate of how much gas came out of the valve.

Patel, one of four EPA officials who inspected the Town of Tonawanda plant that same year, went so far as to estimate the amount of coke oven gas at 173 tons a year.

Prosecutors would not comment on Patel’s estimate – it is not known what percentage of that 173 tons may have been benzene or other toxic pollutants – but it is believed to be high enough that the valve may have at least required a permit.

Patel’s analysis of the bleeder valve – one of three alleged sources of air pollution cited in the criminal charges against Tonawanda Coke – followed the disclosure in court Friday that the company claimed the emissions were infrequent and minimal.

“The PRV opens very rarely,” the company said in a 2009 report about the valve. “Should the valve open, it would only be for 5 to 10 seconds. The PRV has not opened for months.”

Patel is the first EPA official to testify before the jury and Chief U.S. District Judge William M. Skretny about the amount of coke oven gas that came from the valve. Several current and former Tonawanda Coke employees have testified that the valve opened every 20 to 30 minutes and usually stayed open for 10 to 20 seconds, sometimes longer.

Courtroom testimony that coke oven gas with benzene was released into the air came as the debate over the health of residents living in and around Tonawanda’s industrial corridor continues to rage.

State health officials recently released data showing elevated levels of certain cancers and birth defects among neighborhood people. The report, which stopped far short of identifying a cause, was prompted by an air quality study that found concentrations of benzene and formaldehyde much higher in the Tonawanda area than other industrial and urban areas.

Patel said EPA’s review of the bleeder valve’s operations led to a civil Notice of Violation against the company, an action defense lawyers took issue with in view of Tonawanda Coke’s plan to remove the bleeder valve.

“You were not aware that the company was planning to deactivate the pressure relief valve, correct?” asked Gregory F. Linsin, a lawyer for Tonawanda Coke.

“Correct,” answered Patel.

Patel, when questioned later by Assistant U.S. Attorney Aaron J. Mango, testified that the Notice of Violation was based not on the company’s future plans, but on its past use of the bleeder valve.

He also disagreed with the defense’s contention that Tonawanda Coke’s characterization of the emissions as “de minimis” may have been justified if it was based on the valve’s use in late 2009, and not during the inspection several months earlier.

“You don’t think that would be reasonable?” asked defense attorney Rodney O. Personius.

“No, I don’t,” answered Patel.

The bleeder valve is one of three alleged sources of air pollution cited by the government in its indictment of Tonawanda Coke and fellow defendant Mark L. Kamholz, the company’s environmental controls manager.

The others are two “quenching towers” used to cool the hot coke produced at the plant. The company is accused of not equipping its towers with baffles, a piece of equipment used to reduce the particulate matter in the coke oven gas that results from the cooling.

Personius and Linsin tried to poke holes in the government’s case by suggesting there are inconsistencies and discrepancies in how state and federal officials oversaw the plant’s use of the two towers.

“Were you aware that the New York State Department of Environmental Conservation had granted this facility an exemption for Quench Tower No. 1,” Linsin asked at one point.

“I was not aware of it,” Patel answered.

“Do you agree that you should have been aware of it?” Linsin asked.

“If I had reviewed the DEC records, I would have been aware of it,” Patel said.

Linsin also asked Patel if he was aware that the state had cited Tonawanda Coke for violations at only one tower while the EPA cited both towers.

Patel said he was not aware of the difference in violations.

In addition to the Clean Air Act violations, Tonawanda Coke and Kamholz are accused of violating a federal law known as the Resource Conservation and Recovery Act. The law covers the storage and treatment of coal tar sludge, one of the byproducts of making coke.