Nov. 11—Avista Utilities on Friday announced its plan to start relighting natural gas appliances for more than 36,000 customers who have been without the service since Wednesday afternoon.

It hopes to restore service to all customers on the Palouse, in the Lewiston-Clarkston Valley and surrounding areas by the end of Tuesday. This is the largest natural gas outage in Avista's history.

Avista has completed shutting off service for its customers to allow the system to be repressurized. Its employees will now be going to residences and businesses between 6 a.m. to 10 p.m. every day to turn on their meters and check their appliances. It expected to have more than 500 responders in the area by the end of Friday to start this process, said Avista President Heather Rosentrater.

"This is a serious event that I think most of us will never forget," Rosentrater said during a Friday news conference at Avista's Pullman service center.

The company provided maps that show its step-by-step relighting plan. The first relighting zone, Zone 0, is near where the underground pipeline was ruptured Wednesday afternoon north of Pullman.

According to Avista, it is relighting customers based on the geographic location of its gas infrastructure and which gas lines were able to repressurize first. It is also prioritizing a small group of "critical" customers that include public health and safety buildings, Rosentrater said.

According to Avista, customers will receive notification within 24 hours of their planned relight. An Avista employee will knock on the door of a business or residence and will only enter when an adult is present. Customers are asked not to leave doors unlocked.

Josh DiLuciano, Avista vice president of energy delivery, said crew members will turn on the home or business's meter and check to make sure the pilot lights or electronic ignitions turn on the appliances safely.

Customers do not need to schedule their own relights. There is no cost to customers for relights or gas restoration activity.

If the resident isn't home, Avista will leave a card on the door directing the customer to call Avista to schedule a time to relight.

Avista asks customers to not relight their own systems and to not hire outside professionals to do the job.

Rosentrater said Avista has received assistance from eight other utility companies across the western U.S. to help resolve the gas outage.

Rosentrater and DiLuciano did not comment on specifics regarding the Williams Companies pipeline that was accidentally pierced by a landowner 4 miles north of Pullman on Wednesday.