Northwest Fire District personnel are trying to determine the source of an odor that has sickened several people at an H&R Block office at West Ina and North Thornydale roads Friday night.

Courtesy of Northwest Fire District

Northwest Fire District crews treated two people and evaluated six after they became ill Friday night at a northwest side H&R Block office.

Two people were treated with oxygen at the scene, and the other six were fine after they breathed fresh air outdoors, said Capt. Adam Goldberg, a fire district spokesman.

Shortly after 6 p.m., firefighters responded to an H&R Block office in the 3700 block of West Ina and North Thornydale roads, said Goldberg. 

Office workers and a customer complained of headaches, dizziness and naseau caused by a foul odor.

Firefighters discovered that the odor was from a rubberized roofing material that had not dried, and the fumes were sucked into the air conditioning vents of the building, Goldberg said.

The business closed but will reopen Saturday, said Goldberg.