Toxic chemicals discharged during a fire at an agricultural supply warehouse on the weekend have shut down two popular beaches in Kelowna, B.C.

Pesticides, fertilizers and glycol were washed into a storm drain while firefighters were dousing the flames at the Univar Canada depot, one of several businesses destroyed by fire Saturday night at the Stewart Centre on Kirschner Road.

The runoff turned the water in nearby Mill Creek bright green and killed dozens of small fish before working its way into Okanagan Lake.

Officials in Kelowna have closed off Hot Sands Beach in Kelowna City Park and the beach 500 metres to the south of the Mill Creek entrance to Okanagan Lake, two of the city's most popular beaches.

Provincial and federal health and environment officials are now working on the situation, and water samples have been sent out of province for testing.

It could be a while before the beaches can be reopened, said regional district spokesman Bruce Smith: "At this point they're doing this detailed analysis [of the water]. It's a lot more complicated than just throwing a test strip in your hot tub or swimming pool."

The city's water supply was not affected.

With files from the CBC's Jackie Sharkey