Toolbox explosion rocks New York City hotel

Crews work the scene of an apparent explosion at a construction site for the Viceroy Hotel in Midtown Manhattan July 18, 2013.

Updated at 2:47 p.m. ET

NEW YORK One person was injured after an explosion rocked a Midtown Manhattan building early Thursday morning, CBS New York station WCBS-TV reports.

Fire crews rushed into the Viceroy Hotel after the explosion shook the building shortly before 7 a.m.

"There was a large explosion, the glass was shaking," witness Sean Brown told WCBS-TV.

Sources said a construction worker used a blowtorch instead of a flashlight to see his way to the combination lock on a toolbox, not knowing a canister of flammable gas was being stored inside, WCBS-TV reports.

The flame sparked a powerful explosion that could be felt 27 stories high.

"I got two phone calls to come down, there was an explosion," witness John Piepoli told WCBS-TV. "I gotta get out, obviously."

"It felt like a real big thump when it hit," witness Joe DeJesus, who was in an elevator at the time of the explosion, told WCBS-TV. "That's when we just kept going down all the way, and we just ran out of the building."

Witnesses said the first floor was filled with so much smoke and dust they had trouble finding their way out.

One person was injured in the blast. Witnesses said he was closest to the explosion when it happened.

"He was the one that caught the explosion, and it hit him in the face, knocked him down, and they took him away," witness Hector Rodriguez told WCBS-TV.

A construction permit was issued for the building on June 19. The hotel's website says it's accepting reservations for stays starting Nov. 1.

The city's Department of Buildings cited improper storage of compressed gases as the cause of the explosion and has issued a partial stop work order, WCBS-TV reports.

Fire officials and police spent several hours examining and photographing canisters outside the building while investigators assessed the stability of the structure before allowing workers and union officials back inside.