The Environmental Protection Agency's internal watchdog says the EPA had the authority and enough information to issue an emergency order to protect residents of Flint, Michigan, from lead-contaminated water as early as June 2015 - seven months before it declared an emergency.
Inspector General Arthur Elkins says the Flint crisis should have generated "a greater sense of urgency" at the EPA to "intervene when the safety of drinking water is compromised."
Flint's drinking water became tainted when the city began drawing from the Flint River in April 2014 to save money.
The impoverished city of 100,000 north of Detroit was under state control at the time.
Regulators failed to ensure water was treated properly and lead from aging pipes leached into the water supply.