Election officials in Milwaukee are recounting more than 30,000 absentee ballots because doors on the ballot tabulators were not properly sealed.

The recounting was being done “out of an abundance of caution,” said Melissa Howard, spokesperson for the Milwaukee Election Commission.

There was no reason to believe that any ballots already counted had been tampered with, she said.

Howard said they were taking the step of recounting all of the ballots in an effort to be “completely, fully transparent.” The problem was due to human error, she said.

Read more about the recount.