DENVER (CBS4) – A new study about illegal marijuana grow operations shows major health risks for both law enforcement officers who are involved in busts and those who live in homes where the growing is done.

Dr. John Martyny with National Jewish Health, the leader of the study, said the health risk from marijuana grows comes from high levels of mold spores found inside apartments and houses where the plant is grown illegally. The study was done with cooperation from Denver metro area law enforcement agencies and analyzed 30 different grow operations.

Such homes have high levels of humidity to produce the best plants, but that also creates the strongest mold spores. Mold can cause serious upper respiratory problems, even after only a few minutes of exposure.

“We had not expected the levels that we saw,” said Martyny. “They were extremely high, especially when removal happened.”

Agencies in the Denver area continue to raid illegal marijuana grow operations, and as a result of the study agents will now be outfitted with special equipment like respirators during busts.

“Officers we have known were exposed to dangerous molds and spores and one of which was hospitalized in critical condition,” said Ernie Martinez with the Colorado Drug Investigators Association during a news conference on Monday.

Stan Hilkey with County Sheriffs of Colorado also addressed the issue in the news conference, saying he’s concerned about “how much exposure we’ve already had.”

The illegal grow operations usually take place at apartments and foreclosed homes, according to Dave Banes with RMRC Services. Banes’ company does biohazard clean up work.

“There’s no kind of mold that’s healthy to breathe in high levels. All of it is going to cause issues,” he said.

Banes said that while caring for the plants is the top priority of the resident doing the illegal grow, health and safety usually comes last.

“They are more concerned with profit than the health of the occupants or anybody who might be coming in the house later.”

Often times children are the unintentional victims in such illegal operations.

“The dangers are too significant to have a child be in the home where the grow operation is going on,” Martyny said.