Sometimes the most important lessons learned at school don’t come from a classroom.

   They come from how a school reacts to ugly incidents of bias and prejudice. When a principal learns that nasty slurs are being used in the school or that students are being bullied because of their race or ethnicity, it can be tempting to deny it.

   It can be tempting to resort to the old refrain, “That doesn’t happen at our school.”

   But it does. And when it happens, it must be addressed.

   Recently, a principal in the metro Atlanta area had to address bias on campus. Where other school leaders might have denied or minimized the incidents, this one set a positive example by confronting the situation head-on.

   And it wasn’t a pretty situation: A teacher was accused of referring to Latino students as “beaners.” At the same school, which will not be named here due to the nature of these allegations, a student was being bullied because she is Latina.

   It’s enough to upset any parent. Not surprisingly, a parent met with the principal about it. She was accompanied by Jerry Gonzalez, executive director of the Georgia Association of Latino Elected Officials.

   The principal and teacher profusely apologized. The teacher said she didn’t realize the term she used was derogatory, noting that she picked it up from the students. It was a remarkable example of how an intolerant atmosphere can grow within a school, even among adults when they don’t recognize a term as hurtful and offensive.

   The teacher pledged to stop using the term and the principal agreed to add it to the list of curse words students can’t use at the school. These actions send a clear message to students that such language is not acceptable. The principal also pledged to investigate the behavior of some students to get to the bottom of the bullying issue.

   He even indicated that he’s willing to taking additional steps to curb future incidents. The Southern Poverty Law Center’s Teaching Tolerance program has offered free diversity training to the staff as a result.

   The school’s quick, no-nonsense response is commendable. The principal recognized a key responsibility for educators — ensuring all students feel safe and welcome at school.

   This includes recognizing hurtful language that singles out students because of their race, ethnicity, religion or sexual orientation. If adults don’t stop intolerant behavior, students will assume it’s acceptable and engage in it. All too often, bullying begins with name-calling and the casual use of slurs.

   That’s not to say addressing this issue isn’t difficult. Race and ethnicity are sensitive subjects for people. No one wants to bring negative attention to their school. But children learn — and learn to use wisely — vocabulary through instruction. Without direction, these incidents can occur in any school. That’s why it is so important for educators to be prepared to address them.

   The greater offense is for a school to deny that there’s a problem and allow an atmosphere of intolerance to take root. That’s something that shouldn’t happen in any school.