Fire crews, along with PECO, responded to the I-95 overpass on Tennis Avenue around 6:30 p.m.
PECO found a damaged four-inch, high-pressure natural gas main.
Crews spent hours making repairs to the gas main, which forced the highway to be shut down.
Both sides of I-95 have since reopened as of Monday morning.
Authorities have not said who they believe might be responsible for cutting the line.
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