Hazardous materials crews called to an east Allentown neighborhood Friday afternoon were unable to identify the origin of a chemical odor.
The call came in around 1 p.m. to respond to the 700 block of North Godfrey Street.
It came from a homeowner who had been working in his garage and started coughing.
The homeowner, who worked for animal control in Allentown years ago, suspected the chemical odor was coming from cyanide because he recognized the smell.
Officials initially believed the source might have been be sodium cyanide, said Capt. John Christopher of the city fire department.
He said the homeowner has a container of old chemicals used to kill groundhogs, which could contain sodium cyanide. He explained that was the only type of cyanide used in pest control back when the homeowner was working for the city.
The man's symptoms did match those caused by exposure to cyanide, according to Christopher.
A hazardous materials team set up a perimeter around the property and entered the home to see if that old container had been compromised.
They did find the pest control product but the container was not damaged and had not leaked.
The homeowner will have a professional clean-up company get rid of the material.
As a precaution, he was decontaminated and taken to the hospital for observation.
Two city police officers and one firefighter who were the first on the scene also were decontaminated and taken for observation.
Christopher said that was very precautionary but standard protocol because they were the first to come in contact with the chemical.