Editorial: Chief science advisor does New Zealand a favour

Sir Peter Gluckman, once again, has done the country a favour.

The Prime Minister's chief science advisor has, with customary rigour, exploded myths around the management of methamphetamine exposure in New Zealand homes.

His office reports that it could find no evidence that third-hand exposure to residues on household surfaces from meth use — or 'P' as it is widely-known — caused adverse health effects.

This is contrary to the costly approach adopted for a decade. In the absence of clear scientific information — or a refusal to acknowledge the material — it came to be assumed that trace levels of meth posed a health risk, and as a consequence triggered an unnecessary response.

Without an informed policy, the testing and decontamination industry had a field day promoting the idea that all properties were at risk. Terrible crimes associated with methamphetamine use and manufacture helped sustain a climate where virtually anything associated with the drug required a heavy-handed response.

Yet this imprecise measure has been behind the eviction of countless tenants over several years, helped create an industry which in hindsight is mostly unnecessary and imposed enormous economic costs for negligible benefit.

As the report concludes: "Testing for low levels of methamphetamine in residential properties in New Zealand has come at a very high cost."

The document is a reminder of the value of sound, evidential-based policy and it is unfortunate that it was not commissioned some years ago. According to Housing Minister Phil Twyford, in the last four years Housing New Zealand spent $100 million testing and fixing properties believed to be contaminated according to the standards of the time.

State houses were left empty because they were considered unsafe. Tenant's in the past have been evicted because of meth residue, and charged clean-up costs.

The report states: "It is important that guidelines for mitigation measures are proportionate to the risk posed, and that remediation strategies should be informed by a risk-based approach. This means that, because the risk of encountering methamphetamine on residential surfaces at levels that might cause harm is extremely low, testing is not warranted in most cases."

The report makes suggestions which ought to be included in new policy. It argues that testing in residential property should not be automatic but only considered when manufacturing or very heavy use is suspected. It urges reform of the testing industry, so that those who work in it are accredited and produce consistent and credible results.

Discussing the report after its release, Sir Peter made the observation that from the perspective of New Zealand's housing stock, mould was more dangerous than meth. The report itself noted that the risk of being in an "unstable housing situation" was far greater than the risk of exposure to levels of methamphetamine residue.

These remarks should resonate because the provision of secure and warm, dry housing has far-reaching benefits, in terms of individual and family health, and from an economic perspective.