The Department of Transportation said part of Interstate 91 is closed in East Windsor after a truck went down an embankment.
DOT officials said the right and center lanes on the southbound side of the highway are closed between exits 45 and 44.
Officials with the Department of Energy and Environmental Protection said they responded to the accident after motor oil was released from the tractor-trailer's engine. They said about eight gallons were released and Environmental Services, Inc. was called in to help with clean-up.
DEEP officials said the diesel fuel onboard both saddle tanks was pumped.
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One nearby storm drain was impacted by the oil release but the local fire department put a sorbent boom in place and DEEP officials pumped out what they could recover.
DEEP said there is some impacted soil on the side of the road that is being excavated but no waterways were impacted. They said overall, the impact is considered minor.
The accident was reported at approximately 5:05 p.m.
It is unknown how long the lane closures will remain in effect or if there are any injuries.
No additional information was immediately available.