A former senior guard at New York City's main jail complex was arrested on Monday on a federal charge that he deprived a mentally ill inmate of medical aid after he swallowed a corrosive disinfectant.

Terrence Pendergrass, 49, was a captain on duty at Rikers Island in August 2012 when an inmate in the mental health assessment unit swallowed a so-called "soap ball," according to a criminal complaint.

Unaware that rules require the soap ball to be diluted in water, an inexperienced guard gave it to the inmate, Jason Echevarria, so he could clean up sewage flooding his cell, the complaint said. Instead, Echevarria swallowed the ball, which contained highly caustic ammonium chloride, it said.

Over the course of the evening, the inmate, skin discolored, was banging on his door, vomiting and screaming for medical assistance, two guards told Pendergrass, the supervisor of the unit, according to the complaint.

A pharmacy technician told one of the guards that the inmate could die without help, it said.

Pendergrass's response, according to the complaint, was to tell the guards they should only come to him again if they needed to remove a dead body from the cell.

Pendergrass's union said on Monday that the allegations were false, and that he intended to plead not guilty to a charge of violating the inmate's civil rights.

The complaint said that, even after looking through the inmate's cell window, Pendergrass told one of the guards that he did not think the inmate had swallowed a ball and that his cries must have been misheard.

More than six hours after Pendergrass first heard of the inmate's plight, he ended his shift without allowing him medical help, the complaint said. Echevarria was found dead in his cell the next morning, it said.

Could face prison term

Pendergrass, who lives in the New York borough of Queens, is charged with one count of "deprivation of rights under color of law," a federal statute that forbids people granted powers by the government to abuse those powers. If convicted, he could face up to 10 years in prison.

"The Constitution protects the civil rights of everyone, including prison inmates at Rikers," Preet Bharara, the Manhattan U.S. attorney, whose office is prosecuting the case with the Federal Bureau of Investigation, said in a statement.

Patrick Ferraiuolo, president of the Correction Captains' Association, said the allegations were a fabrication. Pendergrass was never told of any medical issue, he said, and the inmate appeared to be well when he checked in with him.

"We believe that he really was railroaded in this," Ferraiuolo said, adding that he believed the guards under Pendergrass were lying to avoid blame.

If Pendergrass really had refused to recognized a medical emergency, there were other jail officials who could authorize treatment, he said, including the captain who took over after Pendergrass's shift ended at 11 p.m.

A lawyer for Pendergrass, who has worked as a correction officer for 18 years and was on a year-long probation period at the time of the incident after being newly promoted to captain, did not immediately respond to requests for comment on Monday.

The city's Department of Correction said Pendergrass was demoted after the death, was charged with violating department policy last month, and was suspended without pay on Monday.

"The unnatural death of any inmate in DOC custody is unacceptable," the department said in a statement. "We are deeply saddened by Jason Echevarria's tragic passing in August 2012 and have fully cooperated with the U.S. Attorney's Office, as we did with the Bronx District Attorney's earlier investigation."

[Image: Man Hands Of The Prisoner On A Steel Lattice via Shutterstock]