Nicor Gas workers responded to a gas leak and remained at the scene after 4:30 p.m. Wednesday. The McHenry County Sheriff's Office sent a Nixle alert about 10:40 a.m. advising people to avoid the area of Bull Valley and Draper roads in Bull Valley while repairs were underway. The leak began when a contractor struck a pipe, Nicor spokesman David Pietryla said. Gas was shut off in the area at 3:21 p.m., Pietryla said. The McHenry County Sheriff's Office and McHenry Township Fire Protection District could not be reached for comment Wednesday. The leak is not a danger to the public, according to the alert.