CALGARY - A natural gas leak on a section of a TransCanada Corp pipeline near Medicine Hat, Alberta, has been safely shut in, TransCanada said on Tuesday. Spokesman Davis Sheremata said the cause of the leak on the Suffield Lateral line was not yet known, and the company did not have details about how much gas had been released. A spokeswoman for Canada’s Transportation Safety Board confirmed the leak had been isolated and that an investigator was expected on the scene later this afternoon. A drop in natural gas pressure on the line was first detected late on Monday. The leak occurred in a rural area. Sheremata said shippers were unable to bring natural gas onto the system at six receipt points, but that there was no impact on deliveries to customers. “Other pipeline operations continue to operate as normal and we continue to meet delivery requirements in the area,” he said.