Hundreds of thousands, including children, could be drinking deadly water.

Axar.az reports citing AA that a new study released Monday has found that hundreds of thousands of Canadians, including children in daycares and schools, have been drinking water contaminated with lead.

Lead is a metal found in the earth’s crust and it can be toxic to humans, particularly children, affecting the brain, liver, kidneys, and bones. Lead can be toxic in even small amounts because it accumulates in the body.

Canadians were unaware of the problem until the release of the study, which took a year to complete with 120 journalists from nine universities and 10 media outlets involved. Included were people from the Institute of Investigative Journalism at Concordia University in Montreal and the Associated Press.

The study reviewed thousands of test results from homes in 32 different cities across Canada. Out of 12,000 tests, a third of the homes exceeded the lead national safety guideline of five parts per billion.

Experts are calling the findings a public health crisis. To date, Canadian government surveillance on lead levels has been lax and results were kept a secret, so Canadians had no idea they were drinking water containing lead that could lead to serious health problems and even death.

There is no national regulation calling for tests of drinking water and if tests are conducted, there is no requirement to make the tests public.