HOUNSFIELD, N.Y. (AP) — A fire in an animal-feed silo triggered an explosion that killed a firefighter at a farm in northern New York where, just three days earlier, a barn blaze killed more than 100 cows.

Authorities say they believe the barn fire Thursday night at North Harbor Dairy Farm in the town of Hounsfield, 60 miles north of Syracuse, might have kindled the explosion at the nearby steel silo Sunday.

"We believe this is a leftover from the first fire ... a re-ignition, more or less," Jefferson County Sheriff's Lt. Michael Peterson said. "It's not unusual to have a rekindle at such a large scene as that. A silo can burn for weeks because of the way they're constructed."

Authorities don't suspect sabotage but haven't ruled anything out, Peterson said, noting that the cause of both fires remains under investigation.

Sackets Harbor's new assistant fire chief, Garrett Loomis, 26, was near the top of the burning silo when it exploded Sunday morning. He was pronounced dead at a hospital in nearby Watertown.

Loomis, a career firefighter in Fort Drum, previously worked in Wilmington, N.C. The son of a retired firefighter, he grew in Sackets Harbor on Lake Ontario's eastern shore and became assistant fire chief in the small community's volunteer department last Tuesday.

His funeral will be held Thursday, said a county fire official, Bob Simpson.

The farm's owners said that they managed to rescue three calves from the 10,000-square-foot barn before it was engulfed in flames, but that two of the calves later died. The barn was loaded with hay.

Copyright 2010 The Associated Press.