A fire in a commercial building on Rte. 22 in Union backed up traffic on the busy highway for several hours on Friday, causing passers-by and local residents to pull out their cellphone cameras.

The fire, reported at 11:22 a.m., caused the highway to be closed. It was re-opened around 3 p.m.

By 11:30 a.m., the fire at Sanders Roofing at 925 Ball Avenue had reached two alarms and went to 3 alarms shortly thereafter.

Clouds of heavy smoke from the blaze could be seen from neighboring towns including Kenilworth and Cranford.

The Union Township Fire Department and mutual aid crews from all over Union County responded, according to Union Township Fire Chief Frederic A. Fretz. Towns responding included Cranford, Springfield and Summit, along with the Union County Hazmat team. The NJ State Police, the Department of Transportation and the Middlesex County DEP helped to re-route traffic around the area.

Fretz said that Sanders Roofing is a large commercial office and warehouse building containing commercial building materials as well as flammable gas cylinders. Fretz said the cylinders — filled with acetylene and propane — were exploding upon crews' arrival. Hazmat was called in to deal with the gas as well as some of the commercial roofing material.

Fretz told Patch that crews were able to contain the fire to Sanders alone, sparing an adjacent strip mall, multi-family condos and nearby industrial uses.

The fire was under control by 12:35 p.m. but crews remained on scene until after 3 p.m.

Reid Edles, president of the Westfield Volunteer Rescue Squad, said the squad received a call for mutual aid and dispatched an ambulance to the scene shortly before noon today to assist Union EMS in setting up their rehab tent and providing rehab to several firefighters. 

"During the rehab process, the Rescue Squad was dispatched to a call for an injured patient (about a mile away) in Union," Edles said. "The rescue squad treated and then transported the patient to the hospital."

Fretz said that mutual aid also covered the station in Union and responded to several calls while Union personnel were at the Sanders' fire.