When a Baltimore County police officer assigned to Chesapeake High School in Essex tried to break up a fight this week, 16 students wound up going to the hospital as a result of exposure to pepper spray. That's something that should trouble school officials, parents and students at the school who might rightly worry that a similar event could happen again.

We can't second-guess the judgment of the officer who decided pepper spray was an appropriate use of force. Police are regularly called on to make split-second evaluations based on the specific nature of threats and the likelihood that not using force could result in even greater harm to the public. Nevertheless, the incident should give school and police officials pause.

According to police, the fight started Tuesday around 11:30 a.m. in the front lobby and involved two boys, ages 15 and 17. The officer who intervened was a county policeman on long-term assignment to the school. Such "school resource officers," as they are called, are trained and equipped the same as regular county patrol officers, and they operate under the same use-of-force rules, which stipulate that police must use the minimum level of force needed to restore order. The idea behind basing officers at the same school for extended periods is that they will become familiar presences to the students, faculty and staff.

Police say that when the officer arrived on the scene of the fight, he first issued a verbal command to both youths to break it up. When that order was ignored, the officer then attempted to physically separate the boys. At that point, school and police officials say, both youths began assaulting the officer. Around this time, another member of the school's staff arrived and managed to pull one of the boys away from the officer, who was still struggling with the second youth.

What happened next is somewhat unclear, but it appears that several minutes later, as the second youth continued to struggle, the officer warned him he would use pepper spray unless he stopped. When the youth ignored that warning, the officer sprayed him with the chemical irritant.

Pepper spray is a nonlethal inflammatory agent that causes temporary blindness, difficulty breathing, runny nose and coughing. The immediate effects last from 30 to 45 minutes, which gives police time to more easily restrain uncooperative subjects.

In this case, however, it appears the boy who was pepper-sprayed managed to break away from the officer briefly and expose other students to particles of the agent clinging to his skin and clothing. That is how other students ended up with similar symptoms and were taken to the hospital as a precaution.

A county police spokeswoman said that although school police rarely resort to pepper spray, there were at least two other incidents during the last school year when it was used. She also pointed out that the officer in question did exactly what police are trained to do in such situations, and that he did not use pepper spray until after lesser levels of force — verbal commands and physical restraint — had failed. Moreover, she argued, even though no weapons were displayed by either youth, the situation was so chaotic that the officer could not know whether one might be produced and acted appropriately to prevent the situation from escalating and endangering others in the building.

Yet even if the police account of what happened is accurate, the fact remains that more than a dozen students who had no part in the fight ended up in the hospital. There will always be cases in which officers have to make quick judgments about how much force is needed to bring a situation back under control. But those judgments are informed by departmental polices. Given how badly this situation turned out, it calls for the police and school officials to reconsider whether the same rules that apply to criminals on the street should apply to students in the school hallway.