Can Meth Residue be Painted Over?
Using Encapsulation as Decontamination Method
Our decontamination and remediation procedures are undertaken using industry best practice to ensure that the dwelling does not pose a future risk to human health and the environment. Each decontamination is different and poses different levels of risk. We draw on a lot of information from Australia and overseas to determine what is considered to be industry best practice.
Simply painting over a methamphetamine-contaminated surface can result in the methamphetamine penetrating the new paint and becoming available on the surface of the building material. Over time as the surface of the paint erodes away due to cleaning or other natural occurrences, the methamphetamine may once again become available.
International research in regards to encapsulation suggests that some of the research tends to be taken out of context in that the goal of the research is to determine if it is viable to the encapsulate where cleaning did not succeed. In that, encapsulation is not a substitute for cleaning and that it should only be used where cleaning has failed and physical removal (i.e stripping) is not feasible.
Often our choices as decontaminators as to what we need to do come down to what is cost effective. We are always willing to work towards a suitable outcome. In that, we are happy to attempt cleaning. We have been successful at decontamination cleaning of varnished timber trims, in that we have got it down to below 0.5 by scrubbing with repeated attempts with 3m abrasive pads and the neutrasol decon system. Essentially we are removing the top layer of varnish and allowing the decon solution to get in and draw out the meth so that it can be rinsed away. Reapplication of varnish or sanding and revarnishing is required after decontamination cleaning. It can be a costly process and has the potential to delay the project, with re-cleaning and retesting, but we will always try and find the correct balance between decon cleaning and removal.
With validation testing, the safety of future occupants and the environment is the goal, not just passing the test, it’s about getting all of the meth in all of the dwelling under 0.5. For a reputable decontamination company, the validation test is about verification of a reputation, not just passing the test.
After the decontamination repainting maybe required. Due to the contamination and the nature of our work we cannot guarantee that painted surfaces, will not require repainting. Encapsulation is not a substitute for cleaning, however, the risks associated with previously contaminated surfaces the are now under the guideline levels can be further reduced by encapsulation or sealing the surfaces.
The Australian Guidelines do not give much clear guidance, but the US EPA Voluntary Guideline and NZ standards go into more detail. (See references below)
Australian Clan Lab Guidelines
Risks associated with contaminated surfaces may further be reduced by cleaning and vacuuming and encapsulation or sealing the contaminated surfaces with layers of oil-based paint, polyurethane or other materials."
U.S. EPA Voluntary Guidelines for Methamphetamine Laboratory Cleanup
"Encapsulation may be performed before the remediation standard has been met if the remediation standard cannot be met after at least three repeated washings [especially in states with exceptionally protective clearance levels (such as 0.05 µg/100 cm2 )] or if the removal of the contaminated material (such as concrete foundations) would compromise the integrity of the structure. If contamination is left in place under these circumstances, it should be fully disclosed in the final report and communicated to the proper authority and property owner."
NZ Standard Testing & Decontamination of Methamphetamine-contaminated Properties
4.3.7 Clean all interior surfaces
220.127.116.11 Decontamination of building materials
Depending on the level of contamination, the decontamination contractor shall communicate with the property owner or agent and decide whether decontamination or removal of building materials is required. This decision will be based on a number of considerations including cost and whether it is cheaper to remove rather than decontaminate the material, and whether the surface is a critical part of the structure that cannot be removed.
4.3.9 Encapsulate structural surfaces
Encapsulation after decontamination is only recommended for structural elements, such as supporting columns that are not safe to remove from the property or asset. Encapsulation shall only be attempted after post-decontamination testing shows that cleaning or coating removal attempts have been effectively exhausted, and levels of contamination cannot be significantly reduced by further cleaning.