After 30 witnesses and four weeks of testimony about coke oven gas, benzene and toxic sludge, the biggest environmental trial in years in the Buffalo area is about to go to the jury.

A federal panel of 12 men and women will decide if Tonawanda Coke is guilty of 18 criminal charges of polluting the environment and a separate charge of trying to hide what it did from government inspectors.

In a Buffalo courtroom, lawyers on both sides spent Tuesday trying to sway the jury.

“To comply or deceive? That’s the question,” Assistant U.S. Attorney Aaron J. Mango told the jury.

Mango said Tonawanda Coke executives repeatedly faced that question over the years, only to choose company profits over public health and safety time and time again.

Tonawanda Coke’s lawyers countered with the argument that the Town of Tonawanda company passed government inspection after inspection, year after year. They cited Tonawanda Coke’s 30-plus years of compliance with environmental regulations and suggested that changed when state and federal regulators stacked the deck against the company as part of a weeklong inspection in April 2009.

“The only thing that changed was a new sheriff came to town,” said Gregory F. Linsin, one of Tonawanda Coke’s defense lawyers.

The case against Tonawanda Coke and Mark L. Kamholz, the company’s environmental controls manager, is a criminal prosecution based on allegations that they violated two federal laws – the Clean Air Act and the Resource Conservation and Recovery Act, the federal law covering the handling of hazardous waste.

At the heart of the prosecution’s case is the allegation that Tonawanda Coke repeatedly spewed coke oven gas with benzene through a pressure-relief valve into the air.

Throughout the trial, Mango and fellow prosecutor Rocky J. Piaggione challenged the company’s claims that the valve rarely opened and that when it did, it opened only briefly.

Prosecutors also contend that the company violated Clean Air Act regulations by using two “quench” or cooling towers that lacked baffles – wood slats designed to reduce the spread of particulate matter from hot coke produced at the plant.

They also have charged the company with violating the Resource Conservation and Recovery Act, which covers storage and treatment of coal tar sludge, one of the byproducts of making coke.

“This was toxic for benzene,” Mango said of the sludge Tuesday. “Toxic and left on the ground.”

The company also faces a single charge of obstructing justice, a reference to the April 2009 inspection and the allegation that Kamholz and others tried to conceal information about the valve from the inspectors.

Linsin told a far different story to the jury and Chief U.S. District Judge William M. Skretny.

He suggested more than once that the government’s case was based on trumped-up charges and a lack of concrete evidence. He also reminded the jury that Tonawanda Coke and Kamholz had a positive reputation among regulators until state and federal inspectors changed the rules in 2009.

“Thirty years of interaction,” Linsin said of the company’s dealings with inspectors. “Those decades of interaction are relevant.”

In responding to Mango’s assertion that money was a motivating factor for the company, Linsin said the company never shied away from making improvements that were necessary and warranted.

He also challenged the government’s view that the small bleeder valve at the core of the case is a major source of air pollution.

“The location of that valve,” he said, noting its prominence along the plant’s coke oven gas line, “should tell you something about the intentions of the company that installed it.”

Rodney O. Personius, Kamholz’s defense lawyer, will give his summation before the jury begins deliberations today.

News Staff Reporter Charlie Specht contributed to this report. email: