By Mike DeNardo

PHILADELPHIA (CBS) — In the bitter cold, crews loaded thousands of fireworks shells for the 6 p.m. and midnight New Year’s Eve displays over Penn’s Landing.

In 20-degree weather, a dozen workers from the fireworks firm Pyrotecnico unloaded explosives from rental trucks and arranged and wired them on barges at the Navy Yard.

Show producer Ken Furstoss says the crew started unloading a day early, to account for a slower pace caused by freezing fingers.

“The weather wasn’t quite as bad as predicted. If it gets down to zero, then it really gets difficult. But the crew’s been brutalizing themselves to get through it,” said Furstoss.

One worker taped hand warmers to the front and back of his hands, to help keep his fingers nimble.

Furstoss says cold weather actually makes for better fireworks displays, because in lower humidity the shells fly higher and burn longer.