Prosecutors on Wednesday asked a Suffolk Superior Court judge to send a drain company owner to prison for seven to 10 years for failing to take safety precautions at a job site where a terrifying trench collapse killed two of his workers in Boston in 2016.

The government requested the penalty for Kevin Lee Otto, 45, during an emotional sentencing hearing. His lawyer asked for probation or a suspended sentence, telling the court Otto “still continues to grieve” for his employees.

Otto was convicted during an October bench trial of two counts of manslaughter and one count of witness intimidation stemming from the deaths of Kelvin Mattocks, 53, and Robert Higgins, 47.

“This was not an accident, but a deliberate set of acts by Kevin Otto,” said Jennifer Lewis, Higgins’s sister, in remarks to the court. Otto, she said, could have protected his workers, but “he chose greed instead.”

Judge Mitchell H. Kaplan listened to family statements and attorneys’ arguments before setting sentencing for 9 a.m. Thursday.

He was at the job site on Dartmouth Street in the South End on the afternoon of Oct. 21, 2016, when a 14-foot trench quickly filled with water after a hydrant collapsed. Mattocks and Higgins were submerged and drowned.

Prosecutors said Otto knew he was supposed to install cave-in protections known as trench boxes at the site, but the necessary safeguards weren’t present when dirt caved in, burying his workers up to their waists before the hydrant collapsed, unleashing a torrent of water.

Prosecutors said that OSHA had informed Otto at job sites in 2007 and 2012 that he needed to install cave-in protections in trenches that were deeper than 5 feet.

Assistant District Attorney Lynn Feigenbaum told Kaplan on Wednesday that Otto “had been warned that this behavior could kill people.”

Kaplan took issue with that, telling Feigenbaum he heard no evidence at trial that Otto was explicitly warned about possible deaths. Feigenbaum replied that Otto had been told of the “extreme danger” at the job sites.

And Higgins’s father, Gerald Biancuzzo, told Kaplan that a stiff sentence will send a message that if contractors skirt safety regulations, “you’re going to pay for it.”

Otto’s lawyers argued at trial that the government couldn’t prove the lack of a trench box caused the hydrant to collapse. The city is responsible for installing hydrants, which are supposed to be equipped with devices called thrust-blocks to keep them stable, but there’s no evidence such safeguards were ever placed on the hydrant in question, the defense maintained.

On Wednesday, Aviva Jeruchim, an attorney for Otto, told Kaplan her client is the sole provider for relatives who live with him, including his elderly mother and son. She said prosecutors are seeking a much higher sentence than those handed down in similar cases and that harsh penalties don’t deter others from committing crimes.

“We have a sad history in this country of hangings and lynchings in public squares,” Jeruchim said. “Clearly that doesn’t work” as a deterrent.

District Attorney Rachael Rollins told reporters after the hearing that she felt the lynching remark was “a little off color.”

She said that prosecutors are “firmly standing” behind their request for significant prison time, and that her team is “confident we’re going to have some accountability for these two families tomorrow.”

Otto faces a maximum prison term of 20 years on each manslaughter count. His company, Atlantic Drain Service, was convicted of the same counts at trial.

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State law says a company convicted of manslaughter faces a fine of up to $250,000, and that authorities “may debar the corporation . . . for a period of not more than 10 years.”

At one point during Wednesday’s hearing, Biancuzzo, the father of Higgins, described his son as “a loving boy, and I loved the man as he got older.”

As he concluded his remarks, Biancuzzo lowered his voice slightly before delivering one final message to his son.

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