Several parents of Chicago Public School (CPS) students filed separate lawsuits on Nov. 12 regarding a carbon monoxide leak that occurred two weeks earlier at Prussing Elementary School in the Jefferson Park neighborhood.

According to the Chicago Sun Times, there are currently six separate lawsuits which allege negligence of CPS for the leak, which occurred on Oct. 30.

The incident quickly made national headlines because it didn’t just involve a small carbon monoxide leak; as CNN and NBC News both reported, 71 elementary school students and eight adults were hospitalized for carbon monoxide poisoning.

Local fire department officials stated that the levels of carbon monoxide were “abnormally high,” but that’s putting it pretty lightly. According to NBC, several young students complained of feeling ill and one student even passed out before school officials placed an emergency call for an ambulance.

When fire officials and an ambulance arrived at the scene, their carbon monoxide alarms went off; additional assistance was called in while the building was evacuated. Fire department workers responded to the call, which had become a “level one Hazmat situation,” and 12 ambulances in total transported students and adults to seven different hospitals in the Chicago metro area.

While the remaining staff and students were taken to another elementary school, the local fire department brought in a mobile AC repair unit to increase ventilation in the school.

Although it is still not entirely clear how high the carbon monoxide levels were, school officials confirmed that the gas leak was caused by the school’s boiler.

Each of the six lawsuits filed against CPS includes two or more counts of negligence on behalf of the students, and two mothers who were helping out with classroom activities at the time of the leak also sued for personal injury damages totaling $700,000.

CPS has not commented on the lawsuits yet. Each lawsuit also names the Chicago Board of Education, School District 229, and the Public Building Commission of Chicago as defendants.

Luckily, it seems that each individual who was treated for carbon monoxide poisoning is recovering — but parents of CPS students are saying that the school’s negligence could have caused irreparable damage.

“Carbon monoxide (CO) is a poisonous gas that is produced when various fuels are not burned completely,” says Stephanie Mischke, Vice President, Total Air, Inc. “Many products we use in our daily life can produce carbon monoxide if they are malfunctioning. It seems the boiler at this Chicago Public School malfunctioned somehow. In our homes, we can safeguard our families by installing a CO alarm that meets the requirements of the current UL 2034 safety standard. A CO alarm can provide some added protection, but it is no substitute for proper use and upkeep of appliances that can produce CO, so make sure to check your appliances for proper operation and have an HVAC company routinely check your furnace and ventilation system.”