Environmental Science and Research says hair samples show 90% of children in houses where there are 'P' labs, have similar levels of exposure to the drug as adult users.
The agency says 32 of the 36 children it tested over the past two years registered very high levels of methamphetamine.
ESR toxicologist Tom Bassindale says this suggests they absorbed or inhaled the drug over a prolonged period of time.
He says he would expect the percentage of affected children to be reflective of the wider picture.
Dr Bassindale says because the children showed similar levels to those of active adult users, this suggests they will also have experienced the same negative health effects such as paranoia or insomnia.
He says anyone living in former 'P' labs could also suffer exposure if the house has not been properly cleaned.