Burying power lines in order to avoid electricity outages is not an option for Toronto Hydro, according to the utility’s CEO in an interview with The Globe and Mail.

Anthony Haines told the newspaper that about one-third of the infrastructure is already buried, but it costs “seven or eight times” as much as not having it buried.

He also points out that the method leaves the power grid vulnerable to other issues such as floods.

Toronto’s widespread power outage is in its sixth day with hydro crews from across the province focusing on repairs.

“We are still saying prepare for the worst,” Toronto Hydro spokeswoman Tanya Bruckmueller told CityNews on Friday morning.

“A lot of streets, we still can’t get down because of the large trees that have come down.”

It’s still not yet known when power will be fully restored.