The impact of New Zealand's 2018 methamphetamine policy on residential contamination.

AIM: Acknowledging the risks of passive exposure to methamphetamine, New Zealand started testing residential properties in 2010 and set a national standard and guidelines in 2016. However, in May 2018, the requirement to test for methamphetamine was eased unless there was a suspicion of a methamphetamine laboratory or high contamination levels. Owing to this policy change, methamphetamine testing drastically reduced. This study examines the impact of the policy change on residential methamphetamine contamination levels in New Zealand. METHODS: Using longitudinal data from 423 residential properties that were tested before and after the policy change, we applied a fixed effects model to examine the impact of the policy change on methamphetamine contamination at residential properties in New Zealand. RESULTS: We found that the policy change is associated with 1.92mcg/100cm2 higher methamphetamine contamination at residential properties in New Zealand, which will likely increase future healthcare costs. CONCLUSIONS: Given the ongoing escalation in methamphetamine usage, the government should revisit the policy change for controlling the passive exposure of methamphetamine to inhabitants of residential properties so that the associated premature deaths, child maltreatment and healthcare cost can be reduced.