TAMPA — The Hillsborough County School District didn't tell parents for more than a year that it was discovering high levels of lead in some schools' drinking water, a Tampa Bay Times investigation has found.

The district announced the results last week, three days after the Times began asking teachers and principals whether they knew about the lead levels in their classrooms.

By then it had ignored for 16 months federal recommendations that said it should disclose the testing.

It still hasn't released the vast majority of test results, including more than 70 showing lower levels of lead that researchers say still can be dangerous for children.

READ: The Hillsborough School District found lead in its water. It didn't tell parents for a year.