BOSTON >> Officials say students at four Boston public schools may have been exposed to lead-tainted water from drinking fountains that were mistakenly turned on too soon.

Boston Public Schools sent automated calls on Wednesday and plans on sending letters to parents of students at the schools.

The schools are among six where testing found elevated lead levels in at least one fountain. The city is spending $300,000 to repair and upgrade plumbing at those schools.

The fountains were on anywhere from a few hours to several weeks.

Turning the fountains on early was blamed on a lack of communication between employees of the school district's facilities department and a contractor.

The school department says health services staffers are available to answer questions from parents. The district has 125 schools.