When a U.S. congressman introduced a bill to strip the federal Occupational Safety and Health Administration of much of its powers to keep workers safe on the job in 1995, labor leaders and advocates across the country fought back with letters and protests.

James — “Jim” — Moran had a different idea.

He and the organization he cofounded and led, the Philadelphia Area Project on Occupational Safety and Health (PhilaPOSH), designed a “Wanted” ad featuring Rep. Cass Ballenger’s mug. The North Carolina Republican’s crime, according to PhilaPOSH: “Conspiracy to maim, injure and kill American workers.” Not long after, the bill died.

That was Mr. Moran — a “selfless champion of the American working class,” said a friend, labor leader Jed Dodd. He never shied from a fight, whether it was against a congressman or a multinational corporate giant that employed thousands in Philadelphia. And while he was utterly serious about the struggle for workers’ rights and social justice, he fought his battles with a grin, a hint of mischief, and always in a baseball cap or a straw hat.

He died in his sleep Saturday, Nov. 21, at his home in the Parkwood section of Northeast Philadelphia, his son, James Moran Jr., said. Mr. Moran had lung and colon cancer, as well as congestive heart failure. He was 81.

Mr. Moran, who grew up poor in Kensington, where his son said “you were either tough or in trouble,” is “a legend in the U.S. grassroots health and safety movement,” said Peter Dooley, director of the national coalition of local worker safety groups, which includes PhilaPOSH. Founded in 1975, PhilaPOSH was the second organization of its kind in the country, one that organized workers in a specific region around health and safety and that advocated for worker-safety legislation at every level of government.

In 1981, Mr. Moran and PhilaPOSH cofounder Rick Engler, along with the Public Interest Law Center, successfully lobbied Philadelphia City Council to pass a Right-to-Know law that required companies to disclose if they were using certain toxic chemicals, despite fierce opposition from the chemical company Rohm & Haas. At the time, it was the strongest such law in the nation, said Harriet Rubenstein, who moved from Nashville to work with Mr. Moran and Engler shortly after the law passed.

“They were the heroes,” Rubenstein said.

Mr. Moran said he and Engler — “an academic type” — were something of an odd couple. In a video interview recorded in February by his friend Ted Lieverman, Mr. Moran laughs recalling how Engler would walk on eggshells Monday mornings, knowing that Mr. Moran’s mood depended on whether the Eagles had won the day before and how bad his hangover was.

While Mr. Moran cared deeply about fighting for worker health and safety, there was another, larger goal to his work at PhilaPOSH: reviving the labor movement. In the Lieverman interview, he said hoped to use the struggle for safety on the job to teach workers how to organize, how “to get back in the fight,” as he put it.

Mr. Moran dropped out of Northeast High School to work at the North American Lace Factory, where he joined his first union, the Textile Workers Union. He worked at union factories for the next two decades, until he was fired for leading a wildcat strike at the electrical manufacturing company Gould ITE — a firing he challenged successfully in a decision by the National Labor Relations Board, though he eventually lost on appeal.

“He came out of a fighting tradition,” said Dodd, general chairman of the railworkers union the PA Federation of BMWED-Teamsters. “He had no problem throwing down the boss. He had a problem with the people who turned to the lawyers and the bureaucrats to fix things for themselves.”

Labor leaders respected Mr. Moran but sometimes questioned his tactics, calling to suggest he’d gone too far by putting out the Ballenger “Wanted” ad or leading workers to the home of Pennsylvania Sen. Richard Schweiker to protest his bill to weaken OSHA.

Mr. Moran was unapologetic. “Well, he wants to kill a law that saves workers’ lives and limbs and lungs,” he’d tell labor leaders about the politicians they were trying to defend. “That would end the argument, usually,” he says in the Lieverman interview.

Mr. Moran was the driving force behind two major Philadelphia labor parades, the Labor Day Parade and Workers Memorial Day, honoring those killed on the job, as well as regular May Day celebrations. When he “and a gaggle of his comrades” revived the long-defunct Labor Day Parade in 1988, just 60-some workers showed up, said his friend Paul Grubb, an organizer at the health-care workers union District 1199c. Now, thousands regularly attend.

And for decades, he held “outrageous” outdoor parties for his birthday every July with live rock music that went late into the night. The entire neighborhood came out for what was known as the “Jim Moran Party,” his son said.

He credited his wife of nearly 50 years, Agnes “Aggie” Moran, herself a labor activist who also worked at PhilaPOSH, with much of his success. “She had all the common sense and I had none,” he says in the Lieverman interview. And at their retirement party in 2005: “Without Aggie Moran, there would be no Jim Moran.” She died in 2010.

Much of Mr. Moran’s life’s work — the struggle to keep workers safe on the job and his efforts to revive the fighting spirit of the labor movement — resonates more deeply during the pandemic, as workers and the dangerous conditions they face have been thrust in the limelight.

In a video tribute to Mr. Moran, Engler says he hopes Mr. Moran’s many victories could be seen as inspiration for the work to come, “at this time when it’s so tempting to see things as going backward.”

“Your work was absolutely critical,” Engler says, “and saved so many lives.”

In addition to his son, Mr. Moran is survived by a daughter, six grandchildren, and nine great-grandchildren.

In lieu of flowers, donations can be made to PhilaPOSH Jim Moran Legacy Fund on the website or to PhilaPOSH, 3001 Walnut Street, 5th Floor, Philadelphia, 19104. A memorial service will be announced at a later date.