Q+A: What you need to know about methamphetamine contamination
Houses contaminated through the cooking or smoking of methamphetamine is a growing issue in New Zealand.
Just one session smoking the Class A drug, also known as P or Ice, could be enough to produce a positive test result.
However lack of national testing standards is a serious problem facing buyers, sellers, agents, landlords, and tenants.
Here's what you need to know about the health implications of living in a contaminated house, and how you can make sure your home is safe:
* Kapiti family homeless after buying meth-contaminated house
* Meth legacy may affect motels, baches, and even cars
* New home buyers face hidden risk of moving in with meth
* P contamination rampant and growing in NZ state homes
How many houses are affected?
While it's impossible to know how many houses have been contaminated, the Real Estate Institute (REINZ) says it's a "serious issue" in New Zealand.
Housing New Zealand's most up-to-date data shows 688 of its properties tested positive for meth between June 1, 2015 and May 27, 2016. This is a 200 per cent increase compared to the previous financial year, when 229 houses tested positive.
Housing New Zealand owns about 64,000 properties.
What are the health implications?
There's a big difference between living in a house where someone smoked methamphetamine, and living in a house that was used to manufacture the drug, National Poisons Centre toxicologist Dr Leo Schep says.
"People living in a laboratory environment risk suffering adverse cardiovascular, respiratory and dermal effects following the exposure to organic solvents, acids, alkalis and other chemicals. However, people dwelling in a house where previous tenants had smoked methamphetamine, and there is some evidence of low concentrations on surfaces, have minimal risks of toxicity.
"The risks would be similar for people who live in a house that had previous dwellers who smoked cigarettes or marijuana. They will have exposure to these drugs but the concentrations will not be sufficiently high enough to cause either psychoactive or toxic effects to people who may have had inadvertent, and brief, dermal contact with these surfaces."
How do you know if you're at risk?
You have several options when it comes to contamination tests: laboratory tests, professional test kits, and at-home test kits. You can buy at-home test kits on TradeMe for just $25, but they can be unreliable.
Laboratory tests, where samples are taken from a number of areas in the house (ideally every room), are the most reliable option, testing company Meth Solutions director Miles Stratford says.
There's no current legal standard for the levels of methamphetamine that make a house uninhabitable, however Ministry of Health guidelines from 2010 establish an acceptable level of less than 0.5 micrograms per 100 square metres.
Stratford says different tests by different people can yield different results.
"The best thing is to go to reputable company that's been operating for a while."
How reliable are the tests?
Baseline tests (Group/Composite tests) give an indication only of the significance of methamphetamine levels in a house. Lab-based testing is the most "sensitive and accurate approach", Stratford says.
Lab tests show a total amount of methamphetamine present. They also show levels of the precursor chemicals amphetamine, ephedrine and pseudo ephedrine.
In-field testing kits give faster results, but are less accurate than lab tests.
"A simple rule of thumb is to sample as many areas as possible and to use lab-based testing,"
"This reduces the likelihood of significant levels of methamphetamine going undetected."
What standards are in place for testing?
In short, there are no standards for methamphetamine testing and clean-up in New Zealand.
In 2010, the Ministry released guidelines which are used by councils to assess risk. While they don't explicitly confirm a safe level, they establish a currently acceptable level post-remediation: less than 0.5 micrograms per 100 square metres.
Guidelines around the world adopt a range of acceptable levels: 0.05-1.5mcgs. These levels shouldn't pose a health risk to most people.
Institute of Environmental Science and Research says it can't comment on testing undertaken by commercial operations for remediation purposes: "Sensitivity and specificity may vary depending on the techniques being employed by different operators."
However it says as far as it knows, there are no testing standards commercial operators must meet.
"A number of overseas jurisdictions have promulgated testing standards. However, Standards New Zealand has recently established a committee that will begin looking at introducing standards for commercial operators."
I'm renting a house: who's responsible for testing?
If landlords rent out a property that is contaminated, they are breaching their obligations under the Residential Tenancies Act 1986, as well as other legislation such as the Building Act and the Health Act.
However there is no obligation for landlords to test their property and, while they must decontaminate it before it is re-tenanted under the Residential Tenancies Act, their duty does not extend to disclosing its history to prospective tenants unless asked.
If they do test a property during a lease, they are required to tell tenants if levels exceed or are likely to exceed acceptable guidelines.
I'm buying a house: who's responsible for testing?
REINZ chief executive officer Colleen Milne says agents are taught to look for suspicious signs, and suggest testing to owners. Agents should also recommend buyers get independent expert advice.
Police and some local authorities have procedures to notify local councils when they identify contaminated properties.
If you're selling a house, you're required to tell prospective buyers of any level of methamphetamine present.
How much does it all cost?
The costs of sorting out contamination vary wildly; low-level contamination may pose no risk to health and not require any action, while high-level contamination can require a property be destroyed.
Costs for detailed testing range from $3000-$10,000. Decontamination can range from $2000-$50,000.
As well as costing a lot of money, this process can take a long time. With rental properties, this can lead to a loss of income. Most people should expect to spend between $10,000-$50,000, plus the cost of reinstatement.
What should you do if your house is contaminated?
Currently, there are no requirements – subject to that which may be imposed by the terms and conditions of some insurance policies – to tell Police or local council about a positive test result. However, it's recommended you do.