Interim guidance on management of low-level illicit drug house residues

This Department of Health (DOH) interim guidance is to assist local government authorities (LGAs) in managing public health risks in residential dwellings contaminated with illicit drug residues, usually at low levels resulting from smoking these drugs (smoke houses). Methylamphetamine (meth, ice) is the most usual contaminant in this regard.

The process outlined is on a recommended voluntary basis for LGAs or owners, except in high or special contamination situations. It is interim since it may be refined as more scientific information and experience are obtained.

This document is not intended for use in the remediation required after the detection or suspicion of a clandestine laboratory (‘clan lab’ used to manufacture an illicit drug). The clan lab contamination is at a more dangerous level, requiring more specific clean-up guidance and training. Refer to the clan lab references cited in this document.

Low-level health risks

Contamination from the smoking of meth or other illicit drugs is due to their volatilisation and settling as a film of residues within the immediate area of use. Very heavy use of meth, such as on a daily basis by more than one person, may result in the deposition of residues near or possibly well above the national Health Investigation Level (HIL) of 0.5µg/100cm2. However, residues from smoking meth are found in much smaller amounts than the residues released by ’cooking meth’, i.e., in the manufacture of meth. Cooking meth can produce residue levels that may be 1000 times above the HIL. The level of contamination and the risk of exposure to residues from smoking meth may well be several orders of magnitude lower.

However, meth contamination is persistent and poses a potential health risk to anyone exposed to it, especially toddlers, young children and pregnant women. The Department supports the need to clean-up any affected property to reduce the potential for harm and future exposure of residents living in the affected meth smoke house.

Meth Desk reports

The Meth Desk is a project initiated by Western Australia Police Force Organised Crime Squad. Under the current reporting scheme, the WA Police notifies the DOH and the Department of Communities if surface tests in an investigated building indicate presence of meth or some other illicit drug residues. The notification includes a range of risk related information such as level of smoking and presence of vulnerable groups like children.

The WA Police Meth Desk report contains positive and negative screening test results for meth and other illicit drug residues including:

  • tetrahydrocannabinol (THC) which is in marijuana or its extract
  • cocaine, also called crack cocaine
  • heroin, highly addictive opiate drug

Sometimes DOH or LGAs may become aware of suspected or known illicit drug house contamination by other means, such as through a direct approach from an owner who has commissioned some surface testing. These cases will need to be managed based on their individual circumstances, but the body of relevant DOH guidance material will be of assistance in this regard and DOH may be contacted by LGAs to provide direct support.


According to the objects and principles in Section 3 of the Public Health Act 2016:

  • Public health practices and procedures should be cost effective and in proportion to the significance of the public health risks and consequences being addressed.
  • If there is a public health risk, lack of scientific certainty should not be used as a reason for postponing measures to prevent, control or abate that risk.

Due to the likely low-level of contamination and the corresponding low health risk posed by smoke house illicit drug residues, any LGA notification to the owner should be to just recommend appropriate cleaning, unless high levels of contamination are demonstrated.

Notification and management process

The notification and management procedure for smoke house contamination is summarised and also depicted graphically below.

DOH receives the Meth Desk report by email from WA Police and sometimes a report or request from other sources. These reports normally will not be legally actionable under public health legislation unless meth or other illicit drug levels are demonstrated by a reliable method to be above the relevant HIL. At present the WA Police is not able to quantify contamination levels.

DOH will assess the report and determine what level of remediation response is appropriate and its legal enforceability. The remediation guidance from the Department might be generally categorised as follows:

  • Type 1 – Negligible risk from contamination. DOH recordkeeping only; not referred to LGA
  • Type 2 – Low-level smoke house contamination. Standard clean-up procedure on a voluntary basis 
  • Type 3 – Documented higher levels of contamination above HIL or possible drug manufacture; triggers DOH situation-specific remediation guidance, and possibly a more rigorous and LGA mandatory management process.

Notification and Management Process

Notification and management process flow

For Type 2 and Type 3 sites, DOH will email the relevant LGA providing a copy of the WA Police Meth Desk report or alternative results, and additional site related advice relating to remediating the contamination.

Type 2

For low-level contamination the local government authority should notify the property owner in writing (Word 375KB). The property owner should be made aware that is it their responsibility to ensure that health risks are addressed, and be provided with the following information:

  • copy of the relevant extracts from the WA Police Meth Desk report
  • copy of the Illicit Drug Smoke House factsheet (Healthy WA)
  • copy of the Interim Guide for Remediation of Low-Level Illicit Drug Contamination, including cleaner procedure compliance statement.

For low-level contamination scenarios, LGA would recommend that cleaning be undertaken and documented in accordance with the DOH procedures outlined in the notification letter. Although DOH promotes the use of cleaners on its accredited service provider list, other cleaning professionals or processes may be used in consultation with DOH in certain low-level contamination situations. LGAs are not required to follow-up the remediation recommendations.

Type 3

In high-risk situations, including where approved testing has demonstrated levels above the HIL, the consequent Department of Health recommended action may be mandatory and take the form of an LGA issuing a Public Health Notice. This guidance will be situation specific, and the DOH clan lab remediation guidance documents are likely to provide the best reference in this regard.

If the local government authority encounters difficulty or refusal by owners to undertake the recommended or mandatory remediation, then contact Department of Health to explore other remediation options on a site-specific basis.

More Information

Environmental Health Directorate
Phone: (08) 9222 2000