LAS VEGAS » Propane tanks exploded on the ground at a hot air balloon ride business near the Las Vegas Strip on Tuesday morning, leaving a 35-year-old man hospitalized with burns to his arm and leg.

The man is one of the company’s pilots, and it appears he was refueling balloon tanks when the blast occurred, said Jeff Chatterton, a spokesman for Vegas Balloon Rides. On-site refueling is routine, and the company isn’t sure which tanks sparked the fire, he said.

The pilot is in good condition and "good spirits," Chatterton said.

The cause of the fire is still being investigated, the Clark County Fire Department said. Two vans towing trailers and two larger propane tanks holding 500 to 1,000 gallons of fuel were venting fire that led smaller propane tanks to explode, Deputy Fire Chief Jeff Buchanan said. No other injuries were reported.

William Reynolds, 26, said he was on his couch on the 37th floor of a high-rise building nearby when he felt a tremble. He went out to the balcony to see "an intense fire." As he started recording the thick black smoke filling the sky, he witnessed the second explosion.

"Flames were shooting out of the area in a very consistent stream," he said in an email.

Clark County Fire crews responded to the blasts shortly after 9 a.m. and had it under control before 11 a.m., preventing the fire from spreading to nearby structures, larger propane tanks and possible ammunition believed to be in a parked vehicle.

The company said its balloon rides launch off-site every day at dawn. Chatterton said he didn’t know if the tanks being refueled were used in that morning’s flight.

Riders typically don’t visit its business south of the Rio casino-hotel, across Interstate 15 from the Las Vegas Strip.

He expects the company won’t be offering rides for at least a couple of days, Chatterton said. He added that he wasn’t sure if the empty baskets that hold passengers were also engulfed in the fire, but he assumed a few may have been destroyed.