The NIOSH 9111 method
NIOSH 9111 is the United States National Institute for Occupational Safety and Health method for collecting methamphetamine from surfaces by wipe sampling. It is the method referenced by Australian guidance and the one our NATA accreditation covers. Its value is consistency: the same area, the same technique and the same controls every time, so results can be compared between rooms, properties and dates.
- A 10 cm by 10 cm template marks a 100 cm² area on a hard surface.
- A solvent-wetted swab wipes the area in overlapping strokes, then again at right angles.
- The swab is sealed, labelled and the location photographed.
- Gloves are changed between every sample and a field blank checks for contamination.
- Samples travel to a NATA accredited laboratory under chain of custody.
Composite or discrete samples?
| Assessment | What it involves | Best for |
|---|---|---|
| DIY instant kit | A swab and test cassette you use yourself. Gives a positive or negative indication in minutes, no number. | A quick first check between tenancies or before an inspection |
| Laboratory composite (screening) | Our technician takes 100 cm² swab samples across the property. They are combined at the laboratory for one average result, but kept so they can be re-run individually. | Routine screening for sales, purchases and tenancy changes |
| Detailed composite | Three to five samples per room on different surfaces, analysed together for a total per room. | A balanced picture room by room when a problem is suspected |
| Detailed assessment (discrete) | Every sample analysed individually, room by room or area by area. The highest accuracy. | When a screening result exceeds 0.5 µg/100 cm², for insurance claims, disputes and remediation scoping |
| Validation testing | A detailed assessment carried out after remediation. | Confirming a property is below the guideline before re-occupation |
A composite is cheaper and answers "is there a problem?". A discrete detailed assessment costs more but answers "where, and how bad?", which is what a remediator, insurer or tribunal needs. Because our laboratory composites keep each swab separate, a high composite can be re-run individually without returning to the property.
How to read your report
- Sample ID and location, with a photo, so anyone can find the spot again.
- Result in µg/100 cm². Below the reporting limit means none was detected at the laboratory's sensitivity.
- Comparison with 0.5 µg/100 cm², the residential investigation level.
- For composites, the average across combined swabs. A composite near the guideline can hide a single hotspot well above it.
- Recommendations: no action, a detailed assessment, or remediation and validation.
Who relies on these reports
Real estate agencies, insurers, banks, local councils, community housing providers, conveyancers and lawyers all use our reports. If yours will be used in a claim or dispute, tell us when you book so we recommend a detailed assessment from the start.
NIOSH Method 9111 compliant
NIOSH method 9111 compliant
All our methamphetamine residue testing is performed in accordance with NIOSH Method 9111. Our reports are regularly used by Real Estate Agencies, Insurance Companies, Property Management Firms, Financial Institutions and other professional entities.
Breakdown:
Laboratory Composites are when multiple 100cm² swab samples are taken within a property but they are all kept, and sent to the laboratory, individually for analysis. The laboratory will take an extraction from each test tube and combine them into a single analysis. The result is an accumulative total of all test tubes and also shows the combined result which can potentially be detected on a single swab sample or spread throughout all the samples.
The samples are all kept separate, if contamination is found they can be re-analysed individually at the laboratory which will then ascertain which sampling location holds the contamination.- Re-analysis is an additional cost per test tube
Laboratory Composite
Screening Assessment
Detailed Assessment
Breakdown: A Detailed Assessment is a room-by-room or area-by-area type of methamphetamine residue testing testing that provides individual analysis per sample. This type of testing is required when a "Screening Assessment" has exceeded 0.5µg - the maximum acceptable level of methamphetamine as set out by the Clandestine Drug Laboratory Remediation guidelines. Each sample is harvested using the NIOSH 9111 method of a methanol soaked gauze sampling an area of 100cm². Samples of each room/area is required to give you a complete overview of the property. This analysis is used by decontamination companies to create a scope of work to bring the property back to habitable levels and for anyone wanting to accurately understand where the contamination is located as the entire property might not be affected therefore only a limited amount of remediation is required.
Detailed composite assessment
Positives
The total areas sampled will provide a very balanced understanding Of the contamination that is present within the room.
Negatives
The analysis cost per room is higher and also the amount of samples taken is 3,4 times more so the labour cost for the technician is higher.
Breakdown
The objective with this screening is to take a minimum of 3 and up to 5 samples per room on different surfaces. The samples then get analysed together to provide an accumulate total of Methamphetamine for the room. This ensures that the reside that is distributed throughout the room does not get overlooked or if fresh painting has occurred that the samples taken will be from not only the painted gprock but also non painted surfaces and air extraction points. It's extremely thorough as so many surfaces in the room have been tested and combined.
If you're not sure which type of methamphetamine residue testing would be best for your situation, ask us for advice. We can make a recommendation based on whether the chances of finding meth residue are high, medium or low, based on what you know about the properties history.
Last reviewed October 2026 by the EnviroForce team