An email, sent to teachers late last month by a Cobb County school administrator, contained inaccurate information about the school board’s decision not to buy new math textbooks and should not have gone out, Superintendent Michael Hinojosa acknowledged Tuesday.

A debate over the board’s decision has raged for months. The textbooks are aligned with Common Core, national standards that specify math and literature concepts students should learn by certain grades. Tea Party activists, who oppose Common Core because it takes away local control, lobbied the board to reject the textbooks.

» MORE: Read the email and Hinojosa's response

Georgia and 44 other states have adopted the standards, which are not mandated by the U.S. Department of Education, but are supported by the Obama administration.

Michelle Mikes, Hinojosa’s math supervisor for middle and high school students, sent out an e-mail to several math teachers that encouraged them to speak out at an upcoming board meeting. Teachers say, by not purchasing textbooks, the board is taking away a crucial teaching tool.

“If you are wanting to encourage the board to reconsider their actions, then you have the chance to speak up as well,” the email read. “I have done everything in my power that I am able to, it is now up to you.”

The email was forwarded to several other teachers, parents and eventually board members. The email wrongly said the board can’t vote on the issue again for the next six years and that the special sales tax money used to purchase textbooks will instead be spent on “building a playground or something of that sort.”

The board can reverse their decision at any time, and the money can’t be spent on other items.

Earlier this month, board members demanded that Hinojosa correct the email, which they said undermined their authority. It also “put fear and anxiety where it shouldn’t be,” said Board member Kathleen Angelucci.

In an email sent to board members and 13,500 employees Tuesday evening, Hinojosa said, “I regret that misinformation was conveyed. However, it is important that moving forward all employees have accurate information about an issue that has a critical impact on our district curriculum.” Attached to the email is a Q&A on the issue.

Hinojosa’s response disappointed board members, who described it as “bland but adequate” and late.

Mikes’ email is a potential problem for Hinojosa, who has attempted to negotiate several alternatives with the board. He has proposed buying books that have been altered to remove references to Common Core; buying online resources for teachers; or buying the originally proposed Common Core textbooks only for middle and high school students.

But several board members say they now believe teachers are protesting their decisions because their boss told them to, not because they wanted to.

Angelucci said she would discuss the superintendent’s email with her colleagues before reacting.

“I’d like to hear what the superintendent’s explanation is for waiting this long to respond and for his reasoning as to his choice of words,” she said.