A federal judge in Alabama ruled on Thursday that Birmingham police department officers violated the civil rights of high school students when officers used chemical spray to subdue them for minor behavioral issues.

The suit, initially filed by the Southern Poverty Law Center in 2010, alleged that school resource officers (SROs) assigned to schools in the Birmingham public school district were routinely resorting to chemical spray to deal with “normal – and, at times, challenging – adolescent behavior”. This included what the US district court judge Abdul Kallon described as non-threatening infractions that are “universal to all teenagers – ie backtalking and challenging authority”.

According to the SPLC, police in Birmingham public schools – whose students are predominantly black – sprayed about 300 students in 110 incidents between 2006 and 2011.

“This is a great victory for students and their families in Birmingham, and it sends a strong message to school officials across the country that it’s time to stop treating schoolchildren like they’re criminals,” said Ebony Howard, the SPLC’s lead attorney in the case.

The chemical spray in question, “Freeze +P”, is a military-grade mixture of pepper spray and teargas designed to cause “strong respiratory effects” and “severe pain”, according to the product’s manufacturer. One plaintiff recalled that being sprayed felt like “needles stabbing [her] face”, and several noted significant trouble breathing after inhaling the compound.

In his ruling, Judge Kallon said “the court was profoundly disturbed by some of the testimony it heard at trial. The defendant S.R.O.s uniformly displayed a cavalier attitude toward the use of Freeze +P.”

In one of the incidents depicted in the trial, a 15-year-old student who was five months pregnant at the time, identified only as KB, had been involved in a verbal altercation with a male student. She testified that as she walked away from the male student, screaming and cursing, Officer Silburn Smith approached her, handcuffed her and told her to calm down. KB insisted she was calm, although she acknowledged she was crying hysterically, and she said that Smith then sprayed her without warning. KB said “her face felt like someone had cut it and poured hot sauce on it”, and that she vomited shortly after being sprayed. Officer Smith offered a different version of events, but the court found KB’s account more credible.

“While all of the facts in this case are disturbing,” Judge Kallon wrote, “the court is especially taken aback that a police officer charged with protecting the community’s children considered it appropriate and necessary to spray a girl with Freeze +P simply because she was crying about her mistreatment at the hands of one of her male peers.”

At the time of the incident, the pregnant KB was 5ft 4in, and 130lb. Officer Smith, was 6ft tall and 200lb. The judge noted that in their testimony, several SROs conceded they failed to follow regulations which require that officers “consider their own size, physical ability and defensive tactics expertise”, among other factors when choosing the level of force to deploy.

School resource officers are sworn officers in the Birmingham police department and subject to the same use-of-force guidelines that apply to the department.

According to BPD guidelines, chemical spray is an appropriate response to a subject demonstrating “defensive resistance”, like pushing or pulling away from an officer attempting to make an arrest.

However, SROs are allowed to use levels of force more extreme than the level of resistance posed by the subject. Birmingham’s police chief, AC Roper, testified that, according to department standards, chemical spray “can be an appropriate control level in response to verbal noncompliance”.

The SROs were also harshly criticized for failing to decontaminate students who had been sprayed, and simply waiting for the effects of the chemical spray to wear off. “That the officers chose to do so when each of the high schools has science labs with eyewash stations, showers in the locker[ room]s, and bathroom sinks with showers and soap is simply confounding to this court,” Kallon said.

Of the six plaintiffs in the case, Kallon found civil violations had occurred against only two.

The ruling does not prohibit SROs from using “Freeze +P” on students in instances where they present a legitimate threat.

In his ruling Kallon was clear that the proceedings were “not about whether the S.R.O.s assigned to Birmingham city schools can spray students who are actively engaged in a physical fight or other violent behavior with Freeze +P. They can.”

Birmingham police department declined to comment.