UPDATE 7:52 p.m.
While the gas was burning Nyack firefighters went into the burning building at the site to make sure there was no one inside.
Trees and bushes were singed, several utility lines took a beating as well.
UPDATE 7:41 P.M.
Fire companies that responded included Nyack, the Piermont Fire Department and ambulance corps, Sparkill Fire Department, Congers, West Nyack, Central Nyack and Orangeburg.
Nyack Fire Chief James Petriello said they were rotating firefighters in and out of the front lines due to the heat from the fire and the weather.
Also Congers/Valley Cottage Ambulance Corps and Nyack Community Ambulance Corps were on the scene.
With the fire out and the residual gas burned off, business owners were talking with village officials about trying to get back into their businesses on Friday evening. Residents of the affected condos awaited word on getting into their homes.
A 3-block section of North Broadway north of Main Street is still closed.
UPDATE 7:34 p.m.
Eight people were injured after the explosion—most due to the weather. The injured included Nyack firefighters, one who suffered a burn from steam and the other complaining of chest pains. One bystander passed out—a firefighter's relative. Five workers suffered heat exhaustion while trying to repair the problem—one fell to the ground and struck his head.
O&R had to shut off gas at several valves throughout town to stop the flow into the downtown. Officials say the gas plume continued for about 90 minutes after the spark ignited the explosion.
Nyack Chief James Petriello said when they arrived at the fire the flames were ripping into the side of a mixed-use residential and commercial complex. The firefighters quickly put water on the building to prevent fire from spreading. There were seven hose lines. He said they were very lucky to arrive so quickly and prevent the fire from getting into the condo and doing more damage.
Petrillo said that this is the first problem related to the ongoing gas-line replacement project. The work was being done by O&R contractor Raines & Welsh of Haverstraw.
The building sustained fire and water damage; the residents are being kept away.
UPDATE 7:10 p.m.
O&R workers are now swarming over the scene; nearby, fire alarms are still going off.
Despite massive flames that took more than an hour to knock down, only one building—on the north side of North Broadway—was badly burned in the explosion and subsequent blaze.
More than 20 firefighters responded to the rush-hour emergency.
UPDATE 6:38 p.m.
The residual gas is currently burning off, officials said. Meanwhile, 415 customers of the 2,500 who lost power when the explosion occurred remain without power.
UPDATE 6:20 p.m.
A massive fire began at approximately 4:30 p.m. on North Broadway in Nyack Thursday, and was still burning well after an hour.
The blaze was started during O&R's in downtown Nyack, which has been taking place for several months.
"[O&R workers] were replacing a gas main," explained Mike Donovan, O&R's spokesman. "They have to grind into the pipe, which generates sparks."
Donovan said the pipe's stopper did not work properly during this process, however, and the sparks met gas, giving way to stories-high flames.
Donovan said no workers were injured when the flames went up. There are reports of firefighters suffering from minor hear-related injuries, however.
Fire authorities aimed hoses at the blaze from several directions at the blaze, which remained at full-size until about 5:54 p.m. O&R has shut off gas to about 450 local customers.
Near the fire, the temperature was soaring to well above 100 degrees. Firefighters were chugging water bottles and dousing themselves in water to keep cool undeneath their gear.
Police have closed off North Broadway starting at Main Street. About 2,500 O&R customers lost electricity originally; as of 6:12 p.m., only 216 were without electricity.
Dozens of on-lookers were photographing the towering fire. Nyack officials, including Mayor Jen Laird-White and Trustees Doug Foster and Steven Knowlton, were at the scene as well.
Officials said the fire will not affect Nyack High School's graduation.
Stay with Patch for updates, and watch the above video, or browse our photos, for a closer look.