 Firefighters in Elizabeth, New Jersey are battling a four-alarm fire in a large industrial complex just south of Newark Airport.A passerby reported the fire around 5.30 a.m. Friday, according to city spokesperson Ruby Contrerasy Flames could be seen raging through the large industrial buildings. The buildings on fire appear to be located behind a two-block long-street site structure that once housed the first singer sewing machine factory in the United States.In 1873 manufacturing company purchased 32 acres at the site and established the factory where it would make the iconic machines for more than a century, NJ.com reported. It was the largest workforce plant in the world for a single establishment at the time. Public records show the building sold for $1 million in August, authorities have not determined the cause of the fire. There are no reports of anyone inside the building or any injuries.