The fire covered about 30 acres when first discovered at about 9 a.m. in Wharton State Forest and was expected to grow, but no homes were in danger, said Bert Plante, a fire warden with the state's Forest Fire Service.
The fire service in the early afternoon had about 50 workers and fire trucks, bulldozers, three planes and a helicopter fighting the fire, about 25 miles southeast of Philadelphia.
The blaze was difficult to manage because it had moved into a swampy area; no private property was threatened, Plante said.
''With the wind direction and based on it being in a state forest, there aren't any communities in danger,'' he said.
A water and foam mixture was being dumped on the fire from the ground and from the air. Nearby swaths of forest were being set on fire in controlled burns to strip the area of fuel for the blaze.
The Federal Aviation Administration had temporary flight restrictions for three square miles of airspace around the fire. Hammonton Airport was closed so the fire service could fly its aircraft in and out unimpeded.
It was biggest fire of the year so far, but not large as far as New Jersey forest fires go, Plante said.
''I've been around for 25 years, and 260 acres isn't that large,'' he said.
The National Weather Service on Wednesday had most of the state under a ''red flag'' warning until 8 p.m., meaning the weather was ideal for forest fires.
