"Testing for low levels of methamphetamine in residential properties in New Zealand has come at a very high cost," reads the report of the Prime Minister's Chief Science Advisor Sir Peter Gluckman into the national panic over the alleged meth contamination of thousands of properties, which was published today.

"Although promoted as being protective of human health, the actions taken in pursuit of zero risk (which is not achievable in any case) have been disproportionate to the actual health risks," the report finds.

The report validates, in some detail, the scientific critique laid out in a cover story I wrote for Matters of Substance nearly two years ago. It seems to offer a way out of a disastrous situation I had feared was intractable.

Gluckman says that New Zealand's approach seems "unique in the world" in its focus not only on sites where methamphetamine was manufactured but where it might simply have been consumed. He says that "the methamphetamine testing and decontamination industry has promoted the idea that all properties are potentially in danger from methamphetamine contamination."

As a consequence, "there have been huge costs to homeowners, landlords, and the state – not only of testing and remediation itself, but the unnecessary stigma of ‘contamination’ (for example on a LIM report), often based on little or no actual risk."

New Zealand's years of testing fever have come at a cost not only in dollars, but human well-being. Gluckman observes that in a social housing context, "the risk of being in an unstable housing situation is likely to be far greater than the risk of exposure to low levels of methamphetamine residues."

And yet, Housing New Zealand threw people out of their homes and sometimes issued triumphant press releases when the Tenancy Tribunal ordered former tenants to pay tens of thousands of dollars in costs for generally unnecessary remediation. The tribunal itself repeatedly ignored warnings that its apprehension of the science was faulty, often forbidding entry to dwellings that posed no risk to anyone.

This chaos developed gradually from the Ministry of Health's publication of cleanup guidelines for former meth labs in 2010, but really broke the surface in March 2016 with a flurry of stories about the way a new state housing development in Christchurch had been "contaminated". Social Housing Minister Paula Bennett lamented the "serious health effects" on "wee babies" and endorsed Housing NZ's get-tough approach. There was little doubt who the villains were.

It should be noted that Housing NZ did have a genuine problem with a more limited number of properties that had been used for manufacture (it's one that has been steadily diminishing as meth is increasingly trafficked into the country fully made). And no, no one wants a P house for a neighbour. But the women who were evicted, along with their children, in Christchurch may not even have been themselves consuming.

If the story turned when the minister weighed in, it turned back 21 months later when her successor, Phil Twyford, gave an extraordinary interview to RNZ Checkpoint, in which he offered an apology to Auckland man Robert Erueti, who had been evicted from the home where he had lived for 15 years and spent more than a year in emergency housing. Millions of dollars had been wasted, said the new minister, who followed up by commissioning the Gluckman report released today.

Change has been evident in the interim. In the March issue of Matters of Substance Housing NZ CEO Andrew McKenzie contributed a column outlining a fresh philosophy that he said was the result of "a long, hard look at the way we work with our tenants, particularly how we keep them in housing."

McKenzie began his role in September 2016 and is thus accountable for the continuation of the agency's ill-advised policies for some time after that. But you can't read this paragraph without seeing Housing NZ reconnecting with a role it had long seemed deserate to shirk: its role as a social housing provider and not just a property manager.

Tenants will be provided with support that will ensure they have all the tools they need to sustain a successful tenancy for the time they need it. Achieving life skills and housing independence are key planks of this approach. That includes tenants who need a stable home to have the best chance of working through any addiction issues. While our tenants need us, we’ll be there for them.

Armed with Gluckman's report, Twyford will now apply its recommendation that the cleanup standard established last year (1.5 micrograms per 100cm) should only be applied to properties where meth manufacture or what Gluckman describes as "excessive smoking" are suspected. The standard will be treated as what it actually is – a sentinel value for the remediation of contamination by more harmful chemicals – and where there is no reason to suspect actual harm, we shouldn't be testing. It will be harder for the testing industry to distort the science.

Helpfully, the Residential Tenancies Amendment Bill (No 2) – originally designed to give landlords greater power to enter properties and test at will for supposed meth contamination, terminate tenancies on the basis of those tests and claim compensation from tenants – is yet to receive its second reading. The bill has already been somewhat reined in after select committee scrutiny (among other things, it no longer specifically refers to methamphetamine) and Twyford will incorporate the new recommendations in regulations to be attached to the act itself.

So much for the politics. But we also need to contemplate another reason the country got into this mess – the news media.

For years, reporters and interviewers simply nodded while self-proclaimed "experts" with a direct commercial interest in a meth panic made outlandish claims about health risks that did not exist. It was, we were repeatedly told, the new leaky homes crisis.

The influence of the testing industry was evident in more subtle ways too. This text appeared at the bottom of that Stuff story quoting Paula Bennett:

The problem with P * It can cause breathing problems, respiratory irritation, skin and eye irritation, headaches, nausea and dizziness. * High exposures even for a short time can cause death or severe lung damage and skin or throat burns * People can be exposed by breathing the air that may contain suspended contaminant particles as dust, by touching surfaces that are contaminated, by eating or drinking from contaminated dishes, or from eating or smoking after contact with contaminated areas.

It's presented as fact, but none of these things are true of methamphetamine itself. So where did this wording come from? You can find it in various versions on state government websites in the US like this one. But that US site refers solely to contaminants from meth manufacture. The same words appear on the websites of New Zealand testing and cleaning companies, but on those, the harms are attributed to the mere consumption of meth in a property. The information was altered for commercial gain – and the papers printed it.

There is a happier story too. The Science Media Centre demonstrated exactly why its role is so important by releasing this commentary from Dr Nick Kim at Massey University and Leo Schep at the National Poisons Centre, casting expert doubt on the claims that were all over the news. Schep said almost nothing thereafter, but Dr Kim (perhaps because he did not rely on Ministry of Health funding), was happy to explain it to anyone who would listen.

The first to listen – and I do love pointing this out to my journalistic peers – was The Panel on RNZ. Meanwhile, the daily news clamoured with absurd and irresponsible stories pushed by the testing industry.

As the story unfolded, a handful of journalists – RNZ's Benedict Collins deserves special mention here – did very good work. A strikingly uneven Fair Go report on the issue seemed to embody the wider battle between hand-wringing sentiment and scientific scrutiny – the latter coming via Garth Bray, who worked with Dr Kim to demonstrate that the level of meth "contamination" that had the Tenancy Tribunal ordering hazmat suits was in fact present in most of our banknotes.

And I think the Matters of Substance story is one of the most important things I've done. Among other things, I was able to show that Housing NZ's "meth team" had openly countenanced forcing prospective tenants to undergo drug tests as a condition of shelter. (The idea was rejected as impractical, and not on account of its human rights implications.)

Again, there's credit due here – not least to former MBIE staffer Joanne Kearney, who became concerned about what she was seeing as far back as 2014 and started making OIA requests and looking up Tenancy Tribunal decisions. Her willingness to share that information with me made a difference. The same goes for the Housing NZ employees who talked to me. As one of them put it, "we're not monsters".

So good journalism practice won over bad, in the end – but the final cost of the moral panic the media helped foster was significant, in both dollars and wrecked lives. The easy stigmatisation of people with drug problems hurt them, hurt the communities they lived in, and hurt the economy. I truly hope some lessons have been learned in the course of this debacle.