Chemist debunks meth tests

Swabbing walls was not enough to determine whether a house was "more than superficially" contaminated. "If you want to know the full qualitative value of a jelly donut, you don't just skim the icing off the top and declare it 97 per cent sugar." Chemist Dr Terry Smith

Houses with meth-infested wall fibres may sound scary - but one chemist says he would happily live in one.

Tauranga-based chemist Dr Terry Smith helped to set up one of New Zealand’s first trace analysis labs. He said if he did not have a home of his own already, he would ‘‘definitely try to get in on’’ one of the hundreds of methcontaminated homes that lie empty across the country.

‘‘They’d be the cheapest houses around - because of all the stigma attached - and most would be, or could easily be, made safe,’’ he said. Smith calls that stigma ‘‘a hysterical reaction to information the layman doesn’t really understand’’. It can result in decontamination processes costing more than $14,000, which Smith reckons in most cases aren’t necessary.

A ‘‘thorough scrub’’ was enough to get rid of unhealthy levels of meth residue from surfaces, he said.

Meth that had leached into wall fibres, however, ‘‘wasn’t going anywhere but incongruously enough that’s why it’s safe’’.

Smith compared the latter situation to the fine silica particles in concrete, which can lead to lung irritation and cancer if inhaled.

‘‘Are you concerned to walk on concrete? ‘‘No, because you’re not grinding the surface and getting exposed to the silica dust,’’ he said.

‘‘It’s as ridiculous as walking into a zoo and going: My god! I’m close to a tiger, get me out of here!

‘‘If you’re physically separated from it, why be concerned?

‘‘If the tiger sprouted wings and could fly after you - as is the case with more volatile materials than meth - then you’ve got a problem.’’

Meth tests are done through swabbing wall samples.

David Spalter, the director of Residue Testing NZ, recommended six to 10 sample swabs - each costing up to $250 - for an average house. But Smith said swabbing walls was not enough to determine whether a house was ‘‘more than superficially’’ contaminated. ‘‘If you want to know the full qualitative value of a jelly donut, you don’t just skim the icing off the top and declare it 97 per cent sugar.’’

Thirty per cent of the 791 empty houses in Auckland had been deemed uninhabitable due to meth contamination at the end of September, according to Housing New Zealand data. The Ministry of Health announced a loosening of limits at the end of October for houses where the drug had been used but not manufactured.

The new limit for carpeted and uncarpeted houses rose three to four-fold: 1.5 and 2 micrograms per 100 square centimetres respectively. Houses used as meth labs kept their limit of 0.5 micrograms per 100 square centimetres.

Spalter said that while those levels were still ‘‘very low’’, a lack of long-term studies on low-level meth exposure to children meant he would be loath to see them hiked higher.

Just 15 empty Auckland houses were re-classified as inhabitable under the new regulations, Housing New Zealand said.

It did not reveal what levels of meth were found in the houses that would remain empty. - Fairfax NZ