A new study suggests a majority of children who are removed from homes where drugs are produced are healthy and drug free. The study of 75 children who lived in homes where illegal drugs were produced found one-third tested positive for at least one drug.

The Canadian study included children who were referred to a hospital program for assessment after being removed from homes where marijuana was grown or other operations linked to drug production occurred. None of the four children from homes where cocaine was produced tested positive for drugs, while all four children who lived in methamphetamine-producing homes did, Reuters reports.

“Clearly no one should stay in those environments,” lead researcher Dr. Gideon Koren told the news service. He noted, however, that being separated from parents can cause devastating anxiety, so the decision to remove children from drug-producing homes should be made carefully. His findings are published in the Journal of Pediatrics.

Dr. Penny Grant, a pediatrician on the National Alliance of Drug Endangered Children, said some drug-producing environments are more dangerous to children than others. For example, chemicals used in a meth lab can catch fire and explode. She said a very important factor is whether the child’s caregivers are using the drugs they produce.