TTC chief general manager Andy Byford says that a liquid fuel, probably kerosene or fuel oil, is “pouring into the tunnel” near the College station. Byford said it is the City’s belief that the fuel is coming from a nearby building, perhaps a hotel, which uses fuel oil. He said that maybe a tank had cracked after a cold winter and a Spring thaw. Mr. Byford said he was very surprised to find the amount of liquid on the tracks and beside them when he inspected the site personally. He had thought that it was only a trickle. It is coming through an expansion joint in the concrete walls and ceiling of the tunnel. Work has now begun to try to seal the joint but the fear is that unless the entire joint is sealed the leak will find its way to another location. Byford said the sealing and cleanup might take two or three hours but he had to concede that it was possible the subway would not be operating for the afternoon rush hour. Electric subways such as the Yonge system create sparks in normal operation and the risk of a serious fire is behind the need to shut it down the line until the fuel is cleared.