Tenants and homeowners could be exposed to methamphetamine poisoning by P-lab cleaners who need no specialist training to do the work.
Fuelled by the growing use and production of meth in New Zealand, a number of companies have sprung up claiming to be cleanup or testing services.
However, there are no qualifications required to set yourself up as a "meth expert". There is no accreditation process for people working in the industry, and the Ministry of Business, Innovation and Employment said no specific regulations covered it.
A house not properly decontaminated can pose serious health risks to its inhabitants. Exposure to the chemicals used to make P can cause breathing difficulties, itchy and runny eyes, coughing, lung irritation, liver and kidney disease, and increased risk of cancer.
Ministry of Health guidelines from 2010 are the only standards applied to decontamination work.
MBIE said the companies were subject to the Fair Trading Act, which did give some legal recourse if a decontamination job was not done properly.
Joanne Kearney, MBIE's team leader consumer issues, said it was concerned about the potential for abuse. "The problem is undetectable to the homeowner, and it is also highly emotive and involves the potential for harm."
The Fair Trading Act makes it illegal to mislead consumers, give them false information or use unfair trading practices.
MethSolutions director Miles Stratford, whose company does sampling of properties and sends them to a laboratory for testing, said there was no accreditation for companies offering meth decontamination services.
"On the cleaning side of things, there are training programmes, designed to show people how to do it [but] nobody out there is accredited."
Tara-Jayne Stapleton, of Crime Scene Cleaners, said test results after cleaning were provided to councils to show they were below the Ministry of Health guideline levels of 0.5 micrograms per 100 square centimetres.
"There is nothing carved in stone [in the industry] but things have to be done to that standard."
Few people were willing to take the work on, and it was not easy money, she said.
In the United States, where meth addiction has reached epidemic levels in some areas, states decide regulation independent of the federal government.
Ms Stapleton said US rules were much more comprehensive.
A total of 11 meth labs were reported to councils in the Hutt Valley, Porirua and Wellington between 2011 and 2013, according to figures obtained under the Official Information Act.
The Insurance Council reported an anecdotal increase in claims from owners of property used as P labs, but does not collected specific statistics on it.
Wellington City Council said it tracked the records of contractors to ensure they did a good job. Spokesman Richard MacLean said it could recommend reputable cleaners if homeowners were stuck.
"Reputation counts and so, if companies are doing a bad job, then the council, like other organisations, will find out about it sooner rather than later."
The fact a building was a P lab was recorded on its land information memorandum until the test results showed it was below the guideline level of contamination, he said.
DOZEN HOMES TOXIC
Almost a dozen homes have been found to have been contaminated with methamphetamine in the Wellington region in recent years.
However, MethSolutions director Miles Stratford said the true figure would be much higher. "It's the ones you don't know about that are the problem."
Tests on the raided apartment in Chews Lane, central Wellington, have still not confirmed whether the apartment was being used to make meth. Results are due early next week.
A total of 11 meth labs were reported to councils in the Hutt Valley, Porirua and Wellington between 2011 and 2013, according to data obtained under the Official Information Act.
Wellington City Council recorded one meth lab in 2011 and two in 2013.
Mr Stratford said a meth lab cleanup in an apartment building was "potentially a major". "What happens if one of these labs explodes in an apartment building? It doesn't bear thinking about."
For every kilogram of methamphetamine manufactured, 6kg of waste products were created, he said. These could include battery acid, solvents, hydrochloric acid and ammonia. Vapour could get into curtains, cushions and carpets.
Assistant police commissioner Malcolm Burgess and Mr Stratford said meth manufacturers had become mobile, and most labs tended to be in isolated areas.
"We're still seeing some manufacture in cities and built-up areas, but more often it's in locations that are less accessible," Mr Burgess said.
"It's a problem that hasn't gone away. The market will continue to adapt, depending where our enforcement might be."
A total of 34 Housing New Zealand homes were found to be contaminated with methamphetamine nationwide from 2010-11 to 2013-14.
Government relations manager Sharon Girvan said it took a firm line on tenants involved in illegal activity.
HOW TO CLEAN A P-LAB HOUSE
Cleaning up a P lab is a complex and costly business, for professionals only.
Protective clothing, including impermeable gloves, overalls and respirators must be worn.
The property should be comprehensively ventilated.
Vacuuming using a commercial-grade vacuum cleaner is the first step.
Carpeting, wallpaper, paper materials (books, documents) and soft furnishings such as couches and mattresses should be safely disposed of.
All drains should be checked for staining, corrosion and toxic chemicals.
Surfaces should be washed three times with detergent.
It may be necessary to demolish a badly contaminated building.
Walls, ceilings, floors and woodwork must be painted over.
To professionally clean a home of meth can cost tens of thousands of dollars.
METH LAB SIGNS
Unusual chemical smells.
Chemical containers stored or stockpiled.
Stained glass equipment and cookware.
Numerous cold tablet packages lying around or in the rubbish.
Portable gas tanks or other cylinders not normally used in the area.
Chemical stains around household kitchen sink, laundry, toilet or stormwater drains.
Yellow/brown staining of interior floors, walls or ceilings and surfaces.
Unusual activity, especially at night.
- The Dominion Post
Should Wellington have a new convention centre?Related story: $100m Hilton project back to drawing board