Elevated carbon dioxide levels send San Jose middle school students to hospital

The San Jose Fire Department said they were called to Sunrise Middle School on Wednesday morning after they received "reports of multiple patients with difficulty breathing."

After an investigation, the fire department said one of the classrooms contained elevated levels of carbon dioxide and that two students were taken to the hospital. 

Six other students and two adults were evaluated and were taken home by their parents, officials said.  

"We were just working and stuff. And some people started coughing a lot, like really coughing. And the teacher came and tried to see what was happening, and then she started coughing," said Daniel Villalobos, a fifth grader at the school.

The source of the CO2 was removed, the fire department said. 

But they did not explain what that source was. 

Battalion Chief Robert Culbertson did mention that students were doing a "volcano project" with vinegar and baking soda and crews were also looking into whether that contributed to the health scare.

"The reaction of vinegar and baking soda leads to the production of carbon dioxide. And if you are right above where the reaction is you could probably be breathing in some carbon dioxide that could displace the air your body needs," said Dr. Peter Chin-Hong, a professor in the Department of Medicine at UC San Francisco.

Culbertson said that crews got a 911 call at 9 a.m. about eight students who smelled something that made them ill. 

A total of 25 firefighters responded and hazmat crews came in to take air samples from the rear of a particular classroom, Culbertson said.

"Our hazmat team has some very sophisticated tools that can determine any number of substances that may be present in the air," he said.

Despite the scare, school stayed open and the carbon dioxide levels were restored to normal, firefighters said. 

Carbon dioxide appears as a colorless, odorless gas at atmospheric temperatures and pressures. 

Symptoms of mild CO2 exposure may include headache and drowsiness. 

At higher levels, carbon dioxide can cause rapid breathing, confusion, increased cardiac output, elevated blood pressure and increased arrhythmias, according to the USDA.

"There isn’t much to worry about, fortunately. Because the levels of carbon dioxide they were exposed to would be relatively small," said Dr. Chin-Hong, who added being outside in the fresh air was probably the best elixir for this type of exposure.