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) and service providers manage public health risks associated with illicit drug residues contaminating residential dwellings. It is primarily for low level contamination 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 smoke settling as a film on surfaces within the immediate area of use. Very heavy smoking 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 generally found in much smaller amounts than residues left behind by ’cooking meth’, i.e. in the manufacture of meth. Cooking meth can produce residue levels up to 1000 times above the HIL. The level of contamination and the risk of exposure to residues from meth smoking is typically several orders of magnitude lower than that associated with making meth.

However, meth contamination is persistent and may pose a health risk to anyone exposed to it, especially toddlers, young children and pregnant women. The Department recommends  affected properties are cleaned-up to reduce the potential for harm from exposure of residents living in the affected meth smoke house.


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 recommend appropriate cleaning, unless high levels of contamination are demonstrated. This contrasts with the process associated with clan lab notifications for which a clean-up is likely to be made mandatory due to the greater confidence that high levels of illicit drug residues are present.

Identification and management process

In 2017 and 2018, suspected smoke house contamination was notified to DOH or the Department of Housing by the Meth Desk of the Western Australian Police Force. DOH would then pass this information and management advice on to the relevant LGA. This system no longer operates. 

Currently LGAs or DOH become aware of potential smoke house contamination through requests for advice by property owners, agents, tenants or service providers. Without contamination test results being available it is difficult to know whether suspected contamination may be from smoking or making an illicit drug. Therefore, without evidence to the contrary, any contamination should be assumed to be from the far more common process of smoking. Indicators of the different types of illicit drug activities that may be present at a property are provided in Attachment 1 to Illegal drug activity in homes managing risk (PDF 256KB).  

If there is no evidence of drug making and the contamination sampling results are available, these will help determine the likely source of the residues and the most appropriate remediation process. If all samples are at or below 5ug/100cm2 in the case of meth (i.e. not more than 10 times the Health Investigation Level of 0.5ug/100cm2), the contamination can be taken to be as a result of smoking meth. An indicator of drug making is the presence of ephedrine or pseudoephedrine in the swab sample results at higher than trace levels.

Where there is evidence of contamination from smoking meth, or a reasonable presumption of this, then the property can be remediated based on the DOH Interim Guide for Remediation of Low Level Illicit Drug Contamination (PDF 256KB), subject to the next paragraph. 

If contamination levels are above 5ug/100cm2 (even if it is believed residue is only as a result of meth smoking) or there are indications of the possible presence of a clan lab, then the property should be treated as a clan lab and subject to the associated type of remediation as outlined in the DOH Guidelines for notification and risk management after detection of a clandestine drug laboratory (PDF 256KB). Normally the lab would be assumed to be Tier 1, unless there is evidence or large scale or complicated contamination.

If in doubt, the DOH can be contacted to provide advice on what management process may be appropriate.

More Information

Environmental Health Directorate
Phone: (08) 9222 2000