After a Balclutha rental property tested positive for methamphetamine contamination recently, social media has been abuzz with comments accusing some cleaners of scare-mongering over the need for houses to be cleaned to be safe.
University of Otago toxicologist Dr Belinda Cridge said not enough research had been done to make a call on whether meth houses should be cleaned.
If someone had been smoking methamphetamine at a property, owners should take a conservative approach and have their houses extensively cleaned - particularly if children lived there.
``To me, it does have the whiff of some people taking advantage of the situation, but I would rather be conservative, particularly when there are children involved.
``We just don't know.
``There's not a lot of research out there about methamphetamine'' Dr Cridge said.
``There's one article that's come out to say that it does stay on surfaces, and the particular concern seems to be dust.
``If there's dust in the house, then that would act as some sort of reservoir for the chemicals, and the problem with dust is it provides a way for the chemicals to get into the body.''
She said the chemicals were likely to be in walls and carpet, but would they come out and cause harm?
``That's the stuff that nobody really knows.
``We know a little bit more about cigarette smoke, but even our understanding of what happens to cigarette smoke is really only in its infancy.
``So we know that it stays around, we know that there are changes that happen, so the chemicals that you start with are not necessarily the chemicals that are there six months later.
``But there's really no good understanding at the moment of what your exposure might be or how to clean it up.''
She said a good clean with soapy water might do it, but there was no way to know.
If there were young children in the house, who were in that ``really exploratory stage'', she would rip out the carpets, walls and soft furnishings.
``I'd also be concerned if there was mould, because it creates a way for particles trapped in walls to come out easier.
``Mould releases spores, so if there is contamination in the walls, it provides a vehicle for it to get into your lungs where they can cause harm.
``As a parent with two toddlers, I can tell you they stick stuff in their mouth, they crawl on the carpet, they suck stuff, they lick walls ... they do all of that stuff.
``I'd be really careful about it.''
Dr Cridge said she understood why landlords were being particularly conservative.
``Landlords are protecting themselves against [potential] lawsuits down the track.''
Certainly, a house where methamphetamine was cooked carried even more health risks.
``When you're cooking meth, you're using a lot of chemicals that are really volatile.
``The chemicals become airborne and there's a lot of solvents that can attach themselves to things like fabrics, furnishings and carpets, and they will actually come out again.
``How much that happens, how long they stay there for ... there's been no really good studies that answer those questions yet.
``I would be cautious in and around somewhere that has been used to cook it because there is a really nasty raft of chemicals that come off.''
