Benzene, arsenic and other hazardous substances have been known for decades to contaminate the soil and water around the site.
It wasn’t until April 2015 that environmental consultants for the borough discovered 1,4-dioxane there.
Those who monitor the EPA’s cleanup efforts question the accuracy of previous tests for 1,4-dioxane dating to April 2015, when the chemical was first detected at the site.
Related: Outdated tests failed to spot dangerous chemical at Ringwood Superfund site “It shows there isn’t reliability in the sampling or testing methods,” said Michael Edelstein, a Ramapo College professor who has closely monitored the situation in Ringwood for years.
Previous tests by the EPA and Ford failed to look for 1,4-dioxane in Ringwood’s groundwater because their labs were using an older testing method.
How much of a dangerous chemical is making its way through underground aquifers at the Ringwood Superfund site and in nearby brooks is in question after two recent tests of the same water samples showed wildly different results.
Concentrations of the chemical, 1,4-dioxane, were significantly higher in tests conducted in late May by Ringwood’s environmental consultants than those performed at the same time by the Ford Motor Co., according to a report issued this month by the carmaker’s engineers.
The Environmental Protection Agency officials who oversee the site said the different results are not “ideal.” But they said those results will not invalidate prior test results.
The laboratory that Ringwood hired used a technique that experts consider to be more precise and accurate in measuring the chemical, which is believed to cause cancer.Ford, which dumped tons of toxic paint sludge in Upper Ringwood 50 years ago, said it would now use that method, called isotope dilution, in the next round of water tests.