HILLSBOROUGH - Mayor Frank Delcore said Thursday night that the blaze at Veterans Industrial Park is contained to two buildings as firefighters enter their seventh hour tackling the five-alarm fire.

"Say a prayer for the firefighters," Delcore posted on his Facebook page. "They are in for a long night."

Delcore said firefighters will continue working through the night to keep the fire from spreading. They are facing bitterly cold temperatures as New Jersey faces its coldest night this winter. He said the state Department of Environmental Protection and federal Environmental Protection Agency are both monitoring the air quality.

Hillsborough Township Fire Marshal Christopher Weniger told News 12 that as of 10 p.m. firefighters hope to have the blaze under control soon. He reported to them that the fire started in a warehouse containing plastic pellets. The property, owned by the Federal government, is leased to a private company that leases it on to various businesses.

While many residents have contacted the mayor offering food and coffee donations to the firefighters, Delcore said none are needed at this time thanks to assistance from The Salvation Army, which has brought in supplies to those at the scene.

Hundreds of firefighters from across the region have been helping to battle the massive fire, which broke out shortly before 3 p.m. and quickly grew to five alarms.

In order to battle the blaze, pumper trucks have been hooked up to nearby hydrants, filling a convoy of tanker trucks and fire engines with water that is then dumped into reservoirs that feed the water to ladder trucks where firefighters tackle the flames from above.

One firefighter estimated that at least 100 different pieces of firefighting equipment has been brought in the battle the blaze.

Spencer Kent may be reached at skent@njadvancemedia.com. Follow him on Twitter @SpencerMKent. Find the Find NJ.com on Facebook.