Proposed Interim Registration
Case Number 5031
International Maritime Organization (IMO) Environmental Actions for Irgarol
The IMO is the United Nations technical organization responsible for setting safety
, environmental, and other standards for international shipping
The U.S. Coast Guard formally represents the U.S. Government
in the work
of the IMO. It establishes U.S. negotiating positions in close consultation with EPA, National Oceanic Atmospheric Administration (NOAA), Department of State, Navy
, Maritime Administration (MARAD), Department of Justice, and other federal entities.
When the proposal to ban cybutryne (irgarol) was first considered at the IMO in 2017, the Coast Guard consulted with EPA offices (Office of Chemical Safety
and Pollution Prevention, Office of Water
, and Office of International and Tribal Affairs) as well as NOAA, Navy
, Department of State, Department of Transportation, and other federal entities. Following consideration of the
technical merit of the proposal, current
market demand and alternatives, and the anticipated support at the IMO for the proposal, the Coast Guard – with concurrence from EPA and other federal entities – in 2019 expressed “no objection” to the recommendation to go forward with a comprehensive proposal to a ban on the antifoulant paint use.
During the discussions of the proposal at IMO meetings, the Coast Guard and NOAA representatives noted strong support, even among industry entities, for the recommended ban. EPA’s subsequent conversations with industry counterparts, e.g., the American Coatings Association, confirmed that industry agreed that the IMO’s risk assessment was rigorous and
well done and that industry groups do not oppose the ban.
PROPOSED INTERIM REGISTRATION REVIEW DECISION
A. Proposed Risk Mitigation and Regulatory Rationale
In evaluating potential risk mitigation for the applications of irgarol, the agency has considered the risks and benefits. EPA has determined that there are human health
and ecological risks of concern from the use of irgarol in antifoulant paints, preserved paint, and as a materials preservative. However, the agency has also identified areas where risk mitigation measures are appropriate and is proposing to implement label changes for antifoulant paints and preserved paints containing irgarol. Mitigation measures are expected to greatly reduce human health
and ecological risks of concern from the use of irgarol in antifoulant and preserved paints. The
agency has notified registrants of the proposed mitigation measures to address the risks of concern and the registrants are in general agreement with the agency’s proposed mitigation.
1. Proposed Removal of Antifoulant Paint Uses for Irgarol
To mitigate occupational handler inhalation and dermal human health risk as well as the freshwater and marine
ecological exposure risks to aquatic plants that affect coral reefs
, the agency is proposing to remove the antifoulant paint use of irgarol. The agency has been working with the registrants who are planning to cancel their antifoulant paint uses of irgarol along the
same timelines of the IMO (see Section III.C.). EPA understands the most recent IMO recommendation is to ban the use of irgarol (cybutryne) as an antifoulant paint with no new applications as of October 2025 and no existing irgarol-containing coatings after October 2030 unless sealed. Therefore, the agency is proposing that registrants with product labels that include marine
and freshwater antifoulant paints uses must request removal
of those uses by September 30, 2023. If the products are only registered for antifoulant paint uses, then registrants must submit a voluntary cancellation request by September 30, 2023. The timing for the FIFRA 6(f) process and allowing for use of existing stocks is estimated to take 2 years; therefore, the antifoulant paints uses will be effectively cancelled by October 2025, which aligns with current
IMO recommendations. Once all labels are received, the agency will use its FIFRA 6(f) authority to officially cancel the antifoulant paint uses.
The agency would like stakeholder feedback on this proposed timeframe during the comment period for this PID.
Irgarol containing products are currently registered for use in antifoulant paints for boat
and/or vessel hulls in both marine and freshwater settings; as a algicidal preservative in paints, caulks, coatings, sealants, grouts, vinyl roofing, roof coatings, stucco, wood
stains, adhesives, plasters;
and is incorporated into boat
hulls themselves. In antifouling paints, irgarol is often combined with copper, or copper compounds such as cuprous oxide or copper thiocyanate. While irgarol effectively controls algae, copper is effective at controlling aquatic animals
such as mussels and barnacles
. Irgarol is a s-triazine algaecide used in combination with copper in antifoulant paint as a “booster” biocide, intended to diminish algae growth on ship hulls. In material preservative products, irgarol is often combined with carbendazim (MBC), chlorothalonil, and/or DCOIT (3(2H)-Isothiazolone, 4,5-dichloro-2-octyl-).
Currently, there are six registrants with 16 active products in this case; one is a technical product and 15 are end-use products.