EPA Proposes Threshold for Formaldehyde Risk

In a proposed rule published last week in the Federal Register, EPA presents revised hazard values for its risk evaluation of formaldehyde, including a new point of departure (POD) for acute inhalation risk and a new uncertainty factor, and introduces a threshold of 0.3 ppm for EPA’s risk determinations. The proposed rule explains EPA’s conclusion that some conditions of use for formaldehyde previously identified as presenting unreasonable risk to workers and occupational non-users are no longer expected to do so.

Formaldehyde is nearly ubiquitous in the environment and is produced by natural processes, decaying organic materials, and burning. Industry uses formaldehyde to make composite wood products and other building materials as well as plastics, paints, adhesives, and sealants.

EPA’s risk evaluation for formaldehyde was finalized in January 2025. The risk evaluation used the non-cancer reference concentration (RfC) and inhalation unit risk (IUR) for the substance that were developed by the Integrated Risk Information System. IRIS is an EPA program that characterizes chemical health hazards and supplies toxicity information to EPA, other federal agencies, state and local health authorities, and international organizations. To support its proposed rule, EPA cites reports from its Science Advisory Committee on Chemicals (SACC), its Human Studies Review Board (HSRB), and the National Academies of Sciences, Engineering, and Medicine that were critical of the IRIS RfC and IUR values.

EPA’s final risk evaluation for formaldehyde uses an acute inhalation POD of 0.5 ppm and an uncertainty factor of 10 for intrapopulation variability. Following recommendations from the HSRB and the SACC, EPA’s proposed rule uses a POD of 0.3 ppm—the lowest level at which the studies EPA relies on reported irritation in hypersensitive subjects—and an intrapopulation variability uncertainty factor of 1.  

“[T]he POD of 0.3 ppm is protective of effects for all durations, including cancer,” the proposed rule states. “However, if human exposure occurs above 0.3 ppm for a sustained, long-term duration, there is potential for cancer to develop.”

Using the new hazard values, EPA’s proposed rule states that five conditions of use no longer exceed its benchmark for unreasonable risk from formaldehyde exposure for workers and occupational non-users. These conditions of use are lawn and garden products; oxidizing/reducing agents; certain applications of adhesives and sealant chemicals in wood product, plastic material, construction, and paper manufacturing; recycling; and laboratory chemicals.

In a news release, EPA states that it is continuing to work on a risk management rule for formaldehyde.  

Comments on the proposal are due Feb. 2, 2026. Individuals can contribute to AIHA’s comments by completing an online form by 5 p.m. ET tomorrow, Dec. 19.

For more information, refer to EPA’s press release, the formaldehyde risk evaluation, the Federal Register notice, and the docket on Regulations.gov.