One Saturday morning in May 1924, a Mt. Lebanon carpenter named Charles Opferman, his wife, Mary, and three of the couple’s children climbed into the family automobile and began a journey to Downtown Pittsburgh.
West Liberty Avenue was surprisingly congested for a weekend. Hours earlier, trolley workers had declared a strike — the fifth in the past 15 years. South Hills residents traveling into the city had few options other than to drive.
Opferman followed a slow-moving line of smoke-belching automobiles into the mouth of the northbound Liberty Tunnel. Nearly 6,000 feet away, on the tunnel’s opposite end, police officers struggled to guide exiting vehicles onto Carson Street. But there were simply too many cars for the existing tangle of roads. Traffic ground to a halt.
By now the Opfermans were, like dozens of others, trapped inside a tunnel rapidly filling with automobile exhaust that had no place to go — a ventilation system designed to clear the air was not yet operational. The air grew thick. Drivers gasping for breath frantically honked their car horns.
Some people quickly realized the danger. They climbed out of their vehicles and raced toward mouths at both ends of the tunnel. In a few cases, people panicked and, in their dash for fresh air, left companions lying unconscious in motionless vehicles. Many vacant vehicles continued to idle and spew exhaust.
Charles Opferman kept his head. He grabbed a few handkerchiefs, doused them with water from his car’s radiator and bound them around the faces of his wife and children. Then the family rushed to daylight at the tunnel’s northern end.
By then the tunnel was dark with fumes that eerily obscured headlights. The Opfermans joined others groping their way along.
Rescue workers rushing into the tunnel saw the Opfermans staggering out. Some family members had fallen and were being carried by those still struggling forward. When they reached fresh air, all five Opfermans lost consciousness.
Outside the tunnel’s northern mouth, a frantic scene unfolded. Police and civilians rushed into the tubes, pulled stricken passengers from cars and dragged them to safety. Many rescuers were themselves overcome.
One was Charles Eisenbarth, chairman of the Allegheny County road department and the tunnel’s caretaker. On his fourth rescue trip, he stumbled out of the tunnel, struggling to breathe. He thrashed his arms wildly and fought those who tried to help him. A taxi driver named James McCarthy made two trips into the tunnel then lost consciousness. Charles Maire, an electrician at a nearby rail yard, rescued a number of men and women, then tottered 200 yards back to his worksite and collapsed.
Firefighters arrived with gas masks and assisted with the rescue, as did a dozen workers from the federal bureau of mines. Just outside the tunnel, those overcome by gas lay prone on the ground. First aid workers huddled around and offered assistance.
At the tunnel’s south end, motorists and pedestrians waiting to enter heard shouted warnings of danger. Rumors spread that a number of people had died. Drivers diverted their vehicles onto Warrington Avenue, creating space for autos in the tunnel to be backed out.
Newspapers reported that 33 people were overcome. Some were admitted to hospitals and reported in serious condition. Others were treated at the scene and sent home.
A counter determined that a record 649 vehicles entered the southbound tunnel between 7:30 and 8 a.m. on Saturday morning, May 10, 1924. Officials decided they needed to restrict traffic until they could find a solution to the tunnel’s ventilation and traffic problems.
By 1928, engineers had designed a system to keep the air clear even when the tunnel was packed with vehicles.