Methamphetamine-Contaminated Residences in the United States: Assessment of the Environmental Health Significance of Third-Hand Exposure

Objectives: Methamphetamine (meth) use in the United States has been a significant problem for many years. Beyond impacts to the users, two additional consequences of the meth problem are on-going exposure to non-users in contaminated homes and the significant cost of remediation. This study reports the first U.S. national and state-level estimates of the number of contaminated properties, the number of exposed non-users, and the costs associated with remediation. Methods: The ability to estimate these endpoints relies on having random surveys of the frequency or incidence of residential contamination, but such surveys are difficult to perform and therefore scarce. The results of the only identified random survey were used in this study and appropriate geographical and temporal adjustments were made. The overall rate of contamination of Housing Units (HUs) was determined from estimates of the rates of HU contamination by meth smoking, rates of contamination from meth manufacturing, and rates of HU decontamination. Rates equations were integrated to estimate the number of contaminated HUs, the number of people living in contaminated HUs, and potential remediation costs. Results: The random survey found 3.5% of HUs to be contaminated in 2018. Currently, over 5,000,000 (4%) of U.S. HUs are estimated to be contaminated above average health standards. Based on this, the current estimated cost for remediation of all contaminated HUs would be $15 billion per year and $250 billion for the backlog of all currently contaminated HUs. The estimated number of persons currently exposed to meth above average health standards is 13,000,000 people. Conclusions: While the accuracy of these estimates is limited, they indicate that meth-contaminated housing is a significant environmental health and economic issue in the U.S. that has been previously under-recognized. Additional studies of health effects, fate and transport mechanisms, and remediation methods are needed.