RINGWOOD On Jan. 18 more than 700 current and former residents of Passaic County community filed suit against Ford Motor Co. over industrial waste the company left behind 30 years ago. Filing on behalf of 717 residents, Robert F. Kennedy Jr.’s New York practice and the firm founded by the late Johnnie Cochran Jr. alleged the auto maker dumped thousands of tons of paint sludge and other toxic material that contaminated the community’s soil, air and groundwater. The plaintiffs, many of them Ramapo (also spelled Ramapough) Mountain Indians, say some of the waste from Ford’s old Mahwah factory remains even after four federally supervised cleanups. They claim the waste has led to illnesses ranging from skin rashes to cancer, and threatens the Wanaque Reservoir, a key source of drinking water in northern New Jersey. Ford spokeswoman Kathleen Vokes said the company is still reviewing the lawsuit, filed in Superior Court in Passaic County, and could not comment on the specific allegations. However, Vokes said Ford has removed 13,000 tons of impacted soil and paint sludge in the past year, and continues to work with state and local regulators to address concerns. Ford’s groundwater and surface water samplings have found no adverse environmental impact, Vokes added. Last year, the New Jersey Department of Health determined that people in the region suffer from an above-average number of some cancers. New Jersey is home to 135 Superfund sites, named for a federal fund created in 1980 to combine taxes and polluters’ fines to pay for industrial cleanup. No other state has so many designated sites. Ringwood became a Superfund site in 1983, but it was removed from the list 11 years later, after Ford cleaned up tons of toxic sludge. Earlier this month, the EPA’s regional administrator, Alan J. Steinberg, told Ringwood residents that getting the Ford dump site returned to the Superfund cleanup list is a ``very major priority.’’