* Sour gas pipeline breached
* Some residents evacuated as a precaution
* No injuries reported
* Region already hit by flooding
CALGARY, Alberta, June 20 (Reuters) - A pipeline carrying deadly sour natural gas ruptured in Turner Valley in southern Alberta on Thursday, prompting the evacuation of some of the town's 2,100 residents, the Alberta Energy Regulator said.
The regulator said it is working with pipeline owner Legacy Oil and Gas Inc and the government of Turner Valley, about 60 kilometers (37 miles) southwest of Calgary, to respond to the leak of the gas, which contains 1 percent hydrogen sulfide.
"The Town of Turner Valley has evacuated some residents as a precautionary measure. Legacy Oil and Gas has enacted its emergency response plan and is taking measures to manage the incident," the regulator said in a statement.
No injuries have been reported due to the leak.
In small doses, hydrogen sulfide will irritate eyes, nose and throat. But at levels above 100 parts per million it can cause serious injury or even death, according to the Canadian Union of Public Employees.
Turner Valley and many other municipalities in southern Alberta, including the city of Calgary, had already declared states of emergency on Thursday as heavy rains swelled rivers and streams and forced the closure of the TransCanada Highway, the country's main east-west route, near Canmore, 100 kilometers west of Calgary.