On April 28, 2015, EPA announced the availability of a problem formulation and initial assessment document for the Work Plan Chemical 1,4-Dioxane and opened a 60-day public comment period until June 29. The notice also seeks input on EPA's Office of Pollution Prevention and Toxics' (OPPT) initial concerns about the industrial solvent 1,4-Dioxane.
Following receipt of comments on the problem formulation and initial assessment document and consideration of any additional data or information received, EPA will initiate a risk assessment which is the process to estimate the nature and probability of adverse health and environmental effects in humans and ecological receptors from chemical contaminants that may be present in the environment.
1,4-Dioxane is the first chemical for which EPA is releasing a problem formulation and initial assessment document under the TSCA Work Plan Chemical Assessment Program. 1,4-Dioxane is a chemical that is used primarily as a solvent in the manufacture of other chemicals. 1,4-Dioxane is also found as an impurity in anti-freeze and aircraft deicing fluids and in some consumer products [deodorants, shampoos, and cosmetics] (ATSDR 2012; EPA 2006; Mohr 2001). During problem formulation and initial assessment, EPA reviewed previous assessments by EPA and other organizations and additional published studies on the exposure and hazard of 1,4-Dioxane. EPA examined likely exposure and hazard scenarios based on current production, use, and fate information to identify scenarios amenable to risk analysis. The data available and scenarios evaluated for conducting a risk assessment are provided in EPA's TSCA Work Plan Chemical Problem Formulation and Initial Assessment for 1,4-Dioxane. The conclusions of the problem formulation and initial assessment are:
- EPA will further assess potential risks to workers exposed during product formulation and use as a cleaning agent;
- EPA will further assess potential risks to workers and consumers exposed during the use of TSCA-use products that contain 1,4-Dioxane as a contaminant, such as paints, varnishes, adhesives, cleaners, and detergents;
- Risk to the general population through inhalation exposure to ambient air emissions is estimated to be low;
- An assessment of risk from exposure through drinking water is not needed at this time because 1,4-Dioxane is currently being monitored and EPA will determine whether or not regulatory action is needed as part of its Regulatory Determination Process;
- Based on the low hazard profile for 1,4-Dioxane to aquatic organisms, risks to these organisms are expected to be low.
EPA does not have the hazard data needed to determine if there are risks to sediment and soil organisms. Therefore, further analysis of environmental risk is not planned.