Hazmat teams were called to the Passaic River this Monday afternoon.
News Copter 7 was over the scene where the oil slick was spotted along a stretch of the river in Wayne.
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There's no word yet on where the substance came from.
According to Wayne Police, the oil appeared to be small in size and it was only detected on the water's surface.
Crews are working to determine how far downstream the oil traveled.
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