SUPPLEMENTARY INFORMATION:

I. Executive Summary

A. Does this action apply to me?

You may be potentially affected by this action if you are a pesticide manufacturer involved with the International Space Station. The following North American Industrial Classification System (NAICS) code is not intended to be exhaustive but rather provides a guide to help readers determine whether this document applies to them. One potentially affected entity may include Pesticide manufacturing (NAICS code 32532). Other types of entities not listed could also be affected.

If you have any questions regarding the applicability of this proposed action to a particular entity, consult the person listed under FOR FURTHER INFORMATION CONTACT .

B. What is EPA's authority for taking this action?

Under section 18 of the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) (7 U.S.C. 136p), at the discretion of the EPA Administrator, a Federal or State agency may be exempted from any provision of FIFRA if the EPA Administrator determines that emergency conditions exist which require the exemption. EPA implementing regulations are set forth in 40 CFR part 166.

C. What action is the Agency taking?

EPA is announcing receipt of a request submitted to EPA under FIFRA section 18. This notice does not constitute a decision by EPA on the application itself. The regulations governing FIFRA section 18 require publication of a notice of receipt of an application for a specific exemption proposing use of a new chemical ( i.e., an active ingredient) which has not been registered by EPA.

II. Summary of the Request Received

NASA has requested that EPA issue a specific exemption for the use of OPA in the coolant of the internal active thermal control system (IATCS) of the ISS to control aerobic/microaerophilic bacteria in the aqueous coolant. Information in accordance with 40 CFR part 166 ( www.ecfr.gov/​current/​title-40/​part-166) was submitted as part of this request.

As part of this request, the applicant asserts that it has considered the registered biocide alternatives and concluded that OPA is the most effective biocide that meets the requisite criteria, which includes the following: the need for safe, non-intrusive implementation and operation in a functioning system; the ability to control existing planktonic and biofilm-residing microorganisms; a negligible impact on system wetted materials of construction; and a negligible reactivity with existing coolant additives. Without the use of OPA, the ISS lacks an ( printed page 57869) adequate long-term solution to control microorganisms in the IATCS coolant.

The OPA is incorporated into a porous resin material contained in a stainless-steel canister. The canister containing the OPA-incorporated resin is inserted into a coolant system loop, using flexible hose and quick disconnects, and is placed in line for 8 hours to deliver the OPA into the fluid. As the coolant fluid flows through the cannister, the OPA elutes from the resin material into the coolant fluid. The total volume of the circulatory loops of the IATCS is 829 liters. The maximum concentration would be 350 milligrams (mg) of OPA per liter of coolant fluid. A total of 290,150 mg would be needed for the entire system. The OPA is incorporated into the resin at 210 mg of OPA per cm³ resin, resulting in potential total use of 1,382 cm³ of the OPA-containing resin. The level of OPA in the coolant is monitored periodically, and because OPA degrades over time, the concentration decreases to a level that is no longer effective in about 1 to 2 years. At this point, replenishment with new OPA-containing canisters is required.

Since authorizing emergency exemptions in 2011, the EPA expects this use to continue for the duration of the ISS program, which has been extended through 2030.

This notice provides an opportunity for public comment on the application. The Agency will review and consider all comments received during the comment in determining whether to issue the specific exemption requested by NASA.

Authority:7 U.S.C. 136 et seq.

91 FR 57868