A complete water ban affecting about 300 local residents is in effect after five million cubic metres of tailings pond wastewater from the Mount Polley copper and gold mine was released early Monday into Hazeltine Creek.
That's an amount of water equivalent to about 2,000 Olympic-sized swimming pools.
Local residents are calling it an environmental disaster.
- UPDATE | Mount Polley Mine tailings pond dam stabilized, says Imperial Metals
- RAW VIDEO | Aerial view of massive B.C. mine tailings spill
The waterways affected by the ban, which earlier included Quesnel Lake, Polley Lake, Hazeltine Creek and Cariboo Creek, now also include the entire Quesnel and Cariboo river systems right up to the salmon-bearing Fraser River.
Authorities are asking people in the region to stop using water from both rivers.
Those areas are sparsely populated and the Cariboo Regional District has not determined how many additional people have been affected.
The ban does not apply to people in Williams Lake or other towns along the Fraser River.
Authorities had previously said the small town of Likely, B.C., was not directly affected, because it was unclear how many people in the town used water from Quesnel Lake.
But since then, the Cariboo Regional District has decided to start delivering water to Likely because the main supplier of bottled water in the area, a small grocery store, could not keep up with the demand.
Effluent from copper-gold mine operations can include harmful chemicals such as arsenic, mercury, and sulphur.
The district has not received any reports of injuries or people getting sick from drinking water.
After the breach, search and rescue crews removed campers from the immediate area, but shelters have not been provided for them, as they appear to have set up camp elsewhere without any problems, said Cariboo Regional District chair Al Richmond
The mine is located in central B.C. and is owned by the B.C. mining company Imperial Metals.
Testing to take 48 hours
Richmond says the waterways are being tested for contamination.
"I'm hoping that within 48 hours, we're going to have details of what exactly the chemical analysis is," said Richmond.
"Again, we've hit a holiday, so we'll pull all the stops out to get that water analyzed, and I'm sure working with Interior Health and the Ministry of Environment, we'll get that done as quickly as humanly possible."
A helicopter sweep of the area Monday showed a small amount of debris backed into Polley Lake. District officials said the main flow of slurry from the tailings pond went down Hazeltine Creek where it meets Quesnel Lake.
The slurry and an accompanying large pile of debris appear to be stationary. Hazeltine Creek, originally about 1.2 metres wide, is now almost 46 metres wide, washing out the Horsefly Likely Forest Service Road, known locally as Ditch Road.
The water use ban is currently limited to the Mount Polley region and does not extend to Williams Lake or Quesnel to the west.
Waste partially contained in creek
Richmond said most of the waste appears to have been contained in the creek, though some of the material has flowed into Quesnel Lake and Polley Lake.
"The majority of the slurry and the debris was contained at the mouth of the creek," said Richmond. "While there has been some flow of that material into the lake, it hasn't been substantial in consideration of the size of the spill."
The Horsefly-Likely Road, which joins Likely to the town of Horsefly, has been washed out, and authorities have closed it down until cleanup crews finish making repairs.
No property damage reports have been filed, though that may change with time, Richmond said.
The Ministry of Environment said it is working to determine how much environmental damage has been done.
"Further monitoring and testing of waterways will be required before the full extent of potential environmental impacts can be determined," the ministry said in a written statement.
No other details have been released as authorities are still trying to determine the cause and extent of the breach.
A public information line has been set up at 250-398-5581, and updates will be posted to the district's emergency operations Facebook page.