There is no federal drinking water standard for 1,4-dioxane, but as illustrated by a recent press release for the Industrial Excess Landfill Superfund Site in Ohio, the U.S. Environmental Protection Agency (EPA) and state environmental agencies have begun directing potentially responsible parties to conduct investigations to address the presence of 1,4-dioxane in drinking water and groundwater. Some of these investigations are conducted at previously closed sites at which the chemical had not been initially identified as a contaminant of concern. To protect the environment and avoid liability, any business in industries that use or produce this chemical must determine whether it needs to modify its operations to reduce or eliminate 1,4-dioxane.
This client alert surveys the remediation, guidance, and notification requirements for 1,4-dioxane in groundwater across the United States.
I. State Regulations and Guidance
The regulatory landscape for groundwater consists of an array of widely-varying state-promulgated standards and regulations. For example, the lowest allowable concentration is 0.3 µg/L (Massachusetts and Vermont), and the highest value is 200 µg/L (Iowa).
The map and chart are current as of August 29, 2022.
Some states, such as California, have established an advisory Groundwater Information Sheet for 1,4-dioxane. Other states, such as Connecticut, provided an advisory Technical Support Document for 1,4-dioxane (See Table 5). Additionally, some states, such as Missouri, have listed 1,4-dioxane in the Risk-Based Corrective Action Program (MRBCA).
States with No 1,4-dioxane Groundwater Regulations or Enforceable Guidance (as of the date of publication):
Alabama, Arizona, Arkansas, California, Connecticut, Idaho, Louisiana, Maryland, Minnesota, Missouri, New Mexico, North Dakota, Ohio, Oklahoma, Rhode Island, South Carolina, South Dakota, Tennessee, Utah, Virginia, and Wyoming
The regulation of 1,4-dioxane in groundwater will continue over the next several years as additional research is conducted on potential health impacts, and as regulators at both the federal and state levels develop a deeper understanding of the prevalence of 1,4-dioxane in groundwater.