UPDATE: Building OK'd After Strange Odor Hospitalizes 4

Four people were hospitalized, and later released, on Tuesday night after complaining about a strange odor in the former Riverhead Post Office building on West Second Street.

On Wednesday, employees who work in the building were cleared to go back into the building. Though the cause of the incident still remains unknown.

The complaint came in shortly before 6 p.m. Tuesday. Five people were affected in total, though only four were sent to , according to Riverhead Fire Marshal Dave Andruszkiewicz, citing symptoms ranging from breathing problems to sore throat to itchy skin.

Riverhead Police reported that three individials - employees at an office within the building - were hospitalized. 

Early Wednesday afternoon, Andruszkiewicz said he was still unsure what may have caused the problem. He said members of the fire department ran through the building with thermal imaging cameras Wednesday morning and were unable to find a cause. The investigation remains ongoing.

"We're not exactly sure what transpired there," he said.

Riverhead Fire, Police, and Brookhaven Haz-Mat responded to the scene, closing off the street between Roanoke and Griffing Avenues. Members of the Riverhead Volunteer Ambulance Corps transported the individuals to the hospital.

Andruszkiewicz said he believed that whatever caused the problem was an airborne irritant.