Health Standards for Methamphetamine in Residences: One Size Does Not Fit All

Properties that are contaminated with methamphetamine (meth) are sometimes remediated in accordance with state health regulations which contain a health standard for the surface concentration that must be achieved after remedial work is complete. Nearly all states use the same criterion for all parts of the property, even though the extent of dermal and ingestion exposure is related to the occupancy time. For areas such as attics that experience low occupancy time, the high costs of remediation are not justified by exposure considerations. One challenge in defining alternative standards for different space types was the lack of risk-based metrics to use. The analysis reported here provides a framework for determining the exposure differentials as well as the potential cost savings that would occur if alternate standards are set. Low-occupancy space types such as attics, moderate-occupancy space types such as exterior hallways, and HVAC system were evaluated with calculations of frequency of contamination, remediations costs, and incremental exposure/dose to occupants under a broad range of potential standards. Raising very conservative standards set by some states would reduce the average cost to remediate a contaminated house from $18,700 to $15,000 or even $12,500. Substantial remediation cost reductions are likely to be achieved if health standards are based on occupancy time. If all recommended alternate standards are implemented, a further 40-50% cost reduction is possible. These alternate standards still allow the exposure to be within the recommended dose levels, which suggests that these low occupancy spaces are being over remediated. Currently, the high cost of remediation is a burden on thousands of property owners who remediate meth-contaminated property each year, but are also a deterrent to testing suspect properties, resulting in large numbers of contaminated properties remaining occupied.