The trailer overturned in the westbound lanes east of Exit 7 and Route 173 in Bethlehem Township shortly before 2 p.m., according to 511NJ78.
All lanes remained closed as of 3:35 p.m., authorities said.
The Pattenburg Volunteer Fire Company and Bloomsbury Fire Department were assisting at the scene.
Meanwhile, emergency crews were working at the scene of a fully-involved car fire in the eastbound lanes near milepost 20.6 in Lebanon around 12:30 p.m., according to developing reports.
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