Development of Utah's Methamphetamine Decontamination Standard

The following principles were applied while working through the process of determining Utah's decontamination standard:

• The mission of the Utah Department of Health and Human Services is to protect the public's health. The sole objective of this rule is to protect the public from exposure to methamphetamine at a level that could be harmful.
• The state legislature (through passage) and the Governor of Utah (by signing) directed the department to:
  • Consult with Utah's LHDs, and UDEQ. The Conference of Local Environmental Health Administrators (CLEHA) appointed several representatives for the LHDs and UDEQ appointed several staff to serve as consultants to the DHHS to fulfill this requirement.
  • Apply best practices and appropriate methods.
• The Utah Governor's Executive Order EO/013/2011: Establishing Effective Oversite over State Agency Rulemaking. This order directs that the public burdens be minimized.
• The Utah Governor's Executive Order 2017-1: Establishing Effective Oversite over State Agency Rulemaking. This order directs rule making writing style, oversight, and analysis.

When national guidance is lacking, states have two approaches to take in establishing a state standard. The first approach is to use 'national wisdom.' In 2008, when the UDOH first addressed the issue of establishing a standard for cleanup, the nation lacked sufficient scientific evidence to help guide states in this process. As a result, the national wisdom adopted a standard of 0.1 µg/100cm² (read as one tenth of one microgram of methamphetamine per 100 square centimeters of surface area). The justification of that standard was based on the laboratory detection limit. When there isn't enough information to determine a safe level, then no level (or below detection) was thought to be the appropriate standard to set. Since the laboratory detection limit at that time equated to 0.1 µg/100cm², that value was considered the lowest value that could be achieved in clean up and became the standard. In Utah, the UDOH adopted that value as the Utah decontamination standard. At that time, the value was considered the 'best practice and appropriate method.'

Since 2008, a number of investigations into the health effects of low levels of chronic environmental methamphetamine exposure and the mechanical process of exposure have been published. As a result, a few states started investigating the second option which is to determine the standard through science-based exposure modeling.

When there is sufficient data to inform the process, the second approach based on known reference doses and exposure modeling can be used. This process requires knowledge about the exposure process and the dose levels that result in observable adverse health effects. Typically, there are three routes of exposure to environmental contaminates. Those are through inspiration of airborne contaminates; ingestion of contaminated food, water, or hand-to-mouth activities; and transdermal absorption from contact with contaminated surfaces. The modeling process determines how much methamphetamine is transferred (shown by the red arrows) through various compartments (shown by blue boxes) to reach the target organs where harm is done.

Utah adopted and modified the model developed by Colorado. California has a model that is very similar to Colorado's model. The model uses "transfer efficiency factors" (indicated by the red arrows) to move methamphetamine from a surface to the target organs inside the body. Recent investigations into these factors allowed Utah to apply some improvements on the Colorado model.

The resulting dose generated by the model can be compared to a reference dose (RfD). The reference dose is based on the lowest level of exposure for which detrimental effects are observed.

Both Colorado and California included a determination of a reference dose based on the literature available at the time their models were developed. Since that time, additional research has been conducted. EEP used the newer research to calculate a reference dose. Each scientifically validated (peer-reviewed) research report was evaluated by a number of criteria:

The EEP found a paper by Madden et al. that demonstrated permanent behavioral and physiological abnormalities in Rhesus monkeys. That paper found that the lowest observable adverse effect level (LOAEL) was when the body dose was 0.75 mg of methamphetamine per kilogram of body weight (0.75 mg/kg). This LOAEL was used to compute the reference dose (RfD). The computation included adjustments for the differences between a lowest effect level and a no-effect level, humans and monkeys, difference among people, and differences in the environments that people are exposed in. After adjusting for those differences the Utah RfD was calculated to be 0.00025 mg/kg-day.

The dose an infant experiences if the surface is contaminated at 1.0 µg/100cm² (read as one microgram of methamphetamine per 100 square centimeters of surface area) is 0.00024 mg/kg-day. That dose is just below the reference dose and is considered safe. Children and adults have an even lower dose level when exposed to 1.0 µg/100cm². Thus the 1.0 µg/100cm² is the best modeled level for establishing the decontamination standard for infants. It meets the requirements for using best practices and is the least burdensome on the public.

As a result of modeling efforts, in 2010, the DHHS raised the Utah decontamination standard to 1.0 µg/100cm². Nationally, the range of state standards is 0.1 to 1.5 µg/100cm². Thus, Utah also continues to follow the current national wisdom since Utah's standard is within that range. Since that time, additional research has been used to reassess the standard. In 2015, the model was adjusted for improved transfer efficiency factors. The new model resulted in the same decisions for standard setting as the previous model.

California Environmental Protection Agency. Assessment of Children's Exposure to Surface Methamphetamine Residues in Former Clandestine Methamphetamine Labs, and Identification of a Risk-Based Cleanup Standard for Surface Methamphetamine Contamination. February 2009.

Colorado Department of Public Health and Environment. Support for Selection of a Cleanup Level for Methamphetamine at Clandestine Drug Laboratories. February 2005

Environmental Protection Agency. Reference Dose (RfD): Description and Use in Health Risk Assessments. March 15, 1993.

Environmental Protection Agency. Voluntary Guidelines for Methamphetamine Laboratory Cleanup. Revised March 2013.

Madden LJ, Flynn CT, Zandonatti MA, May M, Parsons LH, Katner SN, Henriksen SJ, Fox HS. Modeling human methamphetamine exposure in nonhuman primates: chronic dosing in the rhesus macaque leads to behavioral and physiological abnormalities. Neuropsychopharmacology. 2005 Feb;30:350-359.

Salocks CB, Hui X, Lamel S, Qiao P, Sanborn JR, Maibach HI. Dermal exposure to methamphetamine hydrochloride contaminated residential surfaces: surface pH values, volatility, and in vitro human skin. Food and Chemical Toxicology. 2012 Dec;50(12):4436-40.

Salocks CB, Hui X, Lamel S, Hafeez F, Qiao P, Sanborn JR, Maibach HI. Dermal exposure to methamphetamine hydrochloride contaminated residential surfaces II. Skin surface contact and dermal transfer relationship. Food and Chemical Toxicology. 2014 Apr;66:1-6.

Van Dyke M, Martyny JW, Serrano KA. Methamphetamine residue dermal transfer efficiencies from household surfaces. Journal of Occupational and Environmental Hygiene. 2014;11(4):249-58.