Driver Danny Rodriguez was moving pallets with his forklift Monday afternoon when the hole, 30 to 40 feet wide, 6 to 10 feet deep, opened suddenly, The (Hackensack, N.J.) Record reported Tuesday.
Rodriguez and the forklift fell into the hole and found himself covered from the waist down in a dark, oily liquid, which authorities later said was cooking oil and soy sauce.
Sarah Entena, administrator for AM Express Freight, the warehouse tenant, said the products were typical of the warehouse, which is used for storage of non-perishable foods.
"I saw him [Rodriguez] covered in oil and fluid from the waist down," said Steve Garonyi, a truck driver employed at a nearby firm. "It's amazing he was able to get out."
Rodriguez was hospitalized, the newspaper said.
Property manager Bruce Jordan said it appeared to him the concrete slab floor had given way into a long-forgotten basement.