(CNN) -- Black employees at a Philadelphia, Pennsylvania, waste transfer plant were harassed, humiliated and discriminated against by their supervisor for decades, says an attorney representing two workers who filed a complaint against the city.

Among the allegations in the complaint is that for decades, John Gill, the Northwest Transfer Station's superintendent, limited one restroom to whites only, said the attorney, Howard K. Trubman. The restroom -- which he called the "supervisors' bathroom" -- was supposedly for the sole use of upper-level officials with the city's Streets Department, Trubman said.

As far back as 1996, it became apparent to black employees that they were being slighted, said Trubman. They would watch white co-workers walk into the segregated bathroom, conveniently located one floor above Gill's office.

"If you tried to use the bathroom, you might get suspended," said Leslie Young, a former worker at the facility. Young, along with Gibson Trowery, who still works at the station, filed a complaint with the Pennsylvania Human Relations Commission in October 2007.

Young said he recalled that a lock was placed on the restroom door, with keys distributed only to white workers.

The restroom black workers could use was down five flights of stairs and was "not in the greatest condition," Trubman said. Some employees were forced to ask Gill's permission before they could make the trip, he said.

"It was very degrading and humiliating," said Young. "I saw it wreck peoples' home lives -- picking on you for nothing."

Gill, asked for comment Friday, referred CNN to his lawyers, saying, "If you want to write a fair story, wait for after the trial to finish writing it."

The city solicitor's office, which is defending the case, said, "We don't comment on allegations. ... Based on what we know, we have no reason to believe there is any merit, and that will come clear as the litigation proceeds."

Because the human relations commission was unable to resolve the complaint within a year, Young and Trowery had the option of filing the complaint in the Philadelphia Court of Common Pleas, which they did.

In May, a Philadelphia judge dismissed a separate suit against Gill, leaving the complaint filed against the city intact.

Trubman said they are seeking Gill's dismissal and monetary damages. He expects a trial to begin by next summer.

The issue didn't end with the bathroom at the facility, which is a transfer station where garbage trucks bring citywide waste to be distributed to various landfills.

Black employees complained that they were stuck with the oldest garbage trucks. Whites, they say, were frequently upgraded to newer vehicles.

"Gill would hide the white drivers' keys and pretend that he didn't know where they were," Trowery said. "But I saw him keep the keys in his drawer."

According to Young, in the sweltering summer of 2007, Gill would only allow whites access to a water cooler kept in his barricaded office. Black employees were forced to use a water fountain elsewhere in the building.

"It made me feel like less of a man," said Young. "But I got kids, I got a mortgage. I'm a trash man. I have no college degree -- not too many places I'm going to get a job."

Young said he was a shop steward in 2006 and 2007. It was his job to inform Gill about unhappy workers, he said.

When he told Gill about some resentment felt by some of the employees, he said, Gill launched into a diatribe, saying those unhappy at "the Northwest Plantation Station" could leave.

"As a man I would have put my elbow down his throat," said Young. "You're not going to talk to me like that."

Another former employee at the facility, Walter Bingham, who worked there five years, said that every year on December 31 white workers would be allowed to schedule their vacation times for the coming year, leaving black employees with limited choices.

The problems persisted for more than a decade, Trubman contends. Black workers, led by Young, began to document instances of discrimination in 1999, he said.

"We spent most of our day calming each other down," Young said. "We had people running to his office. [But] everybody has homes and pensions and kids."

Tension between white and black workers ran deep, Young said; the two groups would stick to themselves and hardly spoke.

All About Racial Issues • Philadelphia