A contractor hit a gas mean at a building under construction between East and West Amsterdam avenues, the former site of the Spivak Lighting building, around 9:30 a.m., Sgt. Brian Metzler said.
Adjacent buildings were checked, as well.
One lane of eastbound Route 4 was reopened around 10 a.m. before all lanes eventually were reopened.
A PSE&G crew joined Fair Lawn police and firefighters at the scene.
PHOTOS: Michael Jannicelli
Click here to follow Daily Voice Pascack Valley and receive free news updates.