The hazardous materials emergency that closed westbound Interstate 80 for about six hours Thursday was spurred by a solution containing acetone and tolulene that leaked from the back of a tractor-trailer.
Those chemicals were identified Friday by the Monroe County Office of Emergency Management.
The chemicals were waste product, all mixed into one solution, in the westbound tractor-trailer, which was carrying a total of 40 55-gallon drums, reported Maryellen Keegan of the emergency management office.
"It's nothing you'd want to get on you," said Bruce Henry, deputy director of the county's emergency management office.
A Pocono Mountain Regional police officer who was driving a few cars behind the truck spotted liquid coming out the back and pulled it over around 11:25 a.m. Thursday.
Henry said the police officer, Don Scarfo, noticed the material was getting all over his car and his air-conditioning was sucking in fumes that made him dizzy.
Keegan said the police officer was the only person injured during the emergency. He was overcome by the odor of the chemical mix coming from the truck and had to be taken to the hospital, where he was treated and released.
She said all the chemicals have been cleaned up and no one else was injured.
One of the 55-gallon drums in the back of the truck was corroded and the material leaked out of it, said Henry.
He said that drum was full when it had been loaded on the truck, but only about one gallon of liquid remained in it when the truck was stopped.
Despite the police officer being overcome by the smell, Keegan said haz-mat personnel determined the mix of chemicals did not pose an inhalation hazard.
But she said the interstate had to be closed because it did create a risk of fire or explosion.
Initially the entire interstate was shut down, causing massive traffic tie-ups. Even the northern section of Route 33 approaching Stroudsburg was closed and traffic diverted. All highways reopened Thursday evening.
Keegan and Henry said the heat of the day actually helped with the clean-up, explaining the solution was alcohol-based so it just evaporated.
Keegan said that clean-up including transferring the barrels into another tractor-trailer.
She said the waste in that barrel came from an unidentified paint cleaning company.
Henry said U.S. Environmental, the trucking company, picked up waste chemicals at several locations north of Philadelphia. He believed they were being shipped to upstate New York, but was not sure where.
In addition to the barrels, the tractor-trailer also was carrying cardboard boxes containing waste pesticide. Henry stressed that pesticide, which is a solid, was not involved in the spill.