Meth contamination of property isn’t just an issue for people directly involved in illegal drug activity and their families.
It’s a real, documented health risk for everyday New Zealanders — families, tenants, buyers, and property owners — who unknowingly live in contaminated homes.
A peer-reviewed research study published in the international journal Toxics and referenced by PubMed examined what happens when people are exposed to residual methamphetamine contamination inside residential properties, long after any drug activity has stopped. The findings are highly relevant to New Zealand’s housing market and reinforce why proper testing and evidence-based decision-making matter.
What the Study Looked At
Researchers reviewed 25 real-world case studies involving 63 individuals, including 29 children, who unknowingly lived in meth-contaminated homes.
The properties were contaminated due to:
- Previous meth manufacture
- Meth smoking or use
- Or a combination of both
Importantly, none of the occupants were meth users.
The study combined:
- Surface wipe testing of properties
- Forensic hair analysis to confirm exposure
- Medical and school records
- Interviews and behavioural assessments for children
This makes it one of the most comprehensive investigations into “third-hand” meth exposure — exposure that occurs simply by living in a contaminated environment.
Meth Residue Can Persist for Years
One of the most important findings was that methamphetamine residue can remain in homes for months or even years, even after cleaning, repainting, or renovations.
Residue was found on common household surfaces such as:
- Walls, floors, and carpets
- Doors, cupboards, and handles
- Air-conditioning units
- Areas where children regularly play
Crucially, health effects were reported even in properties with relatively low meth levels, including levels close to current guideline thresholds. This challenges the assumption that “low levels” automatically mean “low risk.”
Health Effects Reported by Occupants
Most participants reported health effects that:
- Began after moving into the property
- Improved or resolved after leaving
Commonly Reported Effects
Behavioural and cognitive changes
- Irritability, aggression, mood changes
- Anxiety and depression
- Fatigue, poor concentration, and memory issues
Sleep disturbances
- Difficulty sleeping
- Vivid or unusual dreams
Respiratory symptoms
- Persistent cough
- Asthma or asthma-like symptoms
- Recurrent respiratory infections
Skin and eye irritation
- Rashes, hives, dry or irritated skin
- Sore, burning, or watering eyes
Children were often more affected than adults, particularly younger children who spend more time on floors, touch surfaces frequently, and place hands or objects in their mouths.
Exposure Was Confirmed — Including in Children
To confirm that exposure was environmental (and not behavioural), researchers conducted forensic hair testing.
Methamphetamine was detected in the hair of more than half of the tested participants, including young children.
In several cases, children had higher detected levels than adults, reinforcing that environmental exposure alone — without any drug use — can result in measurable meth absorption.
Manufacture vs Use: Both Matter
A key takeaway from the study is that there was no clear difference in health outcomes between properties contaminated by meth manufacture and those contaminated by meth use.
This is important, because it challenges the idea that only former “meth labs” are a concern. Repeated or heavy meth use inside a property can also result in contamination levels capable of causing health effects.
The Role of Disclosure — and the Gaps
Many families only discovered contamination after:
- Children became unwell
- Behaviour changed noticeably
- Symptoms improved when they were away from the home
- Neighbours disclosed a prior drug history
In several cases, property owners, agents, or authorities were aware of past drug activity but this information was not disclosed. The study highlights significant gaps in how contamination risks are identified, communicated, and managed.
Why This Matters for Property Owners and Occupants
This research reinforces several critical points:
- Meth contamination is not just a legal or cleaning issue
- It is a health and wellbeing issue
- Children are particularly vulnerable
- Visual inspection or smell alone is unreliable
- Low-level contamination does not necessarily mean no risk
The researchers conclude that residing in meth-contaminated properties can represent a serious public health concern, even when contamination is not obvious.
Scientific advice supplied to government
Government policy on meth contamination is being led by the Ministry of Housing and Urban Development (HUD).
The people in HUD responsible for developing regulation received;
- Advice from Gluckman (Gluckman Meth Report) that included a recommendation that more research should be done.
- Advice from ESR that independent real-world research summarised above pointed to meth contamination being responsible for adverse health outcomes in some people. This was at levels well within those included in the Gluckman Meth Report (15µg/100cm2) and only just over the level recommended by the NZ Standard (1.5µg/100cm2)
- Advice from ESR that there is no scientific basis for adopting a maximum inhabitable level of 30µg/100cm2, based on severe health effects alone.
- Advice from undisclosed sources, that it is not possible to get ethical approval for the type of research needed to definitively prove that the levels included in the Gluckman Meth Report and adopted by a range of government agencies in the time since publication, were in fact safe.
The response of government to scientific advice it has received
Government has not sought to conduct research which increases the confidence the opinions it has relied on when developing policy are correct.
Government has confirmed it will roll out regulation for rental property in 2026 that will run the scientific experiment they cannot get ethics approval for, without any measurement of effect. This regulation will establish at law:
- A level of 15µg/100cm2 above which decontamination will be required.
- A level of 30µg/100cm2 which must be exceeded before termination of a tenancy occurred.
This regulation will further enable meth related behaviour in property. It will make it harder for people to avoid exposure to methamphetamine contamination many times greater than is considered acceptable in any other jurisdiction in the world.
If people wish to protect themselves from the knock-on effect of NZ’s continued and growing fascination with methamphetamine, it is essential they understand the meth status of property.
Full Reference: Wright J, Kenneally M, Ross K, Walker S. Environmental Methamphetamine Exposures and Health Effects in 25 Case Studies. Toxics. 2020 Aug 20;8(3):61. doi: 10.3390/toxics8030061. PMID: 32825457; PMCID: PMC7560285.
