The discovery of a potential asbestos leak has forced the closure of a portion of SaskPower's Boundary Dam power station.
Contractors found the material while rebuilding a generator.
"At this time we can't confirm or disprove the presence of the substance in the air," said SaskPower spokesman Tyler Hopson.
Crews have closed down the area and cleared workers, Hopson added.
Samples of the substance have been sent to a lab so scientists can confirm what it may be, however the tests will take some time.
"It's probably going to be somewhere in the neighbourhood of several days to a week from now when we would know," Hopson said.
While samples are being tested, work in the area of the power station near the discovery has been stopped.
"We want to first of all test and verify that substance, and in the meantime, we've isolated that area so it's not being accessed by employees," Hopson said.
The Boundary Dam Power Station, located near Estevan, Sask., is the largest coal fired station owned by the utility.