The main was struck by an excavation crew Thursday evening.
Washington and St. Clair streets remained closed at and near their intersection into the Friday evening rush hour because of a gas leak that remained under investigation.
Chris Kozak, a Columbia Gas spokesman, said that as of 2:30 p.m., 60 of 81 customers affected by a ruptured gas main at the intersection had service restored.
He estimated the street closings would last until 6 p.m., when repairs would be complete.
The main was struck by an excavation crew Thursday evening. The exact cause and circumstances of that accident remained to be determined, Mr. Kozak said.