9NEWS: The EPA has revoked a testing certification for the Colorado Department of Public Health and Environment’s (CDPHE) water quality lab, after an investigation found a chemist intentionally disregarded protocol in a method that tests for traces of metals, 9NEWS Investigates has learned.

The investigation into the chemist’s actions began in February, according to the state health department, but wasn’t made public until 9NEWS Investigates started asking questions about it last week. State health officials said the data problems may impact as many as 3% of the state’s 2,000 public water systems.

Visit 9NEWS for more.