Document q30rDOyjbdeOReMx1JZNvOD5

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION 8 1595 Wynkoop Street Denver, CO 80202-1129 Phone 800-227-8917 www.epa.gov/region08 Ref: 8WD-SDB November 14, 2023 SENT VIA EMAIL Mr. Jason Wilmot, District Ranger Bridger-Teton National Forest Blackrock Work Center P.O. Box 278 Moran, Wyoming 83013 jason.wilmot@usda.gov Re: Notice of Noncompliance Chemical Phase II/V Rules Maximum Contaminant Level for Ethylene Dibromide PWS ID# WY5680211 C Dear Mr. Wilmot: The purpose of this letter is to inform you that Bridger-Teton National Forest Blackrock Work Center has failed to meet the maximum contaminant level (MCL) for ethylene dibromide under the Chemical Phase II/V Rules. Compliance with the MCL is based on the Running Annual Average (RAA) according to 40 C.F.R. 141.24 of the National Primary Drinking Water Regulations (NPDWR). Our records indicate that the RAA for ethylene dibromide calculated between the second and third calendar quarters of 2023 is 1.4 ug/L. The MCL for ethylene dibromide is 0.05 ug/L as stated in 40 C.F.R. 141.62(c). This is a violation of the NPDWR. Please continue to take the following actions: (1) Sample quarterly for ethylene dibromide at the first hydrant from source sample station, facility/sample point SS01/SP01. (2) Report the quarterly sample results to our office at R8DWU@epa.gov as soon as you receive them from the lab. (3) Provide public notice. 40 C.F.R. 141.203 requires that a system that has violated an MCL notify its customers of the violation as soon as practical, but no later than 30 days, by means including mail or direct delivery to customers and/or posting notices in conspicuous places within the area served by the system. Posting should be continuous and a repeat notice must be issued every three months for as long as the violation exists. Enclosed is a copy of a public notice template that meets all of the federal requirements. You may create your own Tier 2 public notice using the EPA Microsoft Word templates available at: https://www.epa.gov/dwreginfo/public-notification-templates-communityand-non-transient-non-community-water-systems. No later than 10 days after issuing a public notice to its customers, a system is required to provide EPA a copy of the public notice and a certification that the public notice was provided as required in 40 C.F.R. 141.31(d) and 141.203. We appreciate the cooperation and the additional special sampling that Bridger-Teton National Forest Blackrock Work Center has been conducting to determine the extent of contamination and possibly identify a source for the ethylene dibromide. We look forward to continuing to work with you. For any written correspondence with EPA, such as submitting a copy of a public notice and a related certification, please use one of the methods listed below. Include the name of the Public Water System and the PWS ID# on all correspondence with EPA. Email: R8DWU@epa.gov Fax: 1-(877) 876-9101 Mail: Refer to the address at the top of this letter. Please use Mail Code 8WD-SDB on the envelope. You should be aware that violations of Part 141 may potentially result in EPA taking formal enforcement action. Any enforcement action would be based on violations of the Safe Drinking Water Act and/or Part 141. The Safe Drinking Water Act provides for civil penalties of up to $67,544 per day of violation. We prefer to resolve problems before such formal enforcement is necessary and ask your cooperation to rectify problems quickly and effectively. If you have any questions, please contact the Phase II/V Chemicals Rule Manager Kendra Morrison at (303) 312-6145 or by email at Morrison.Kendra@epa.gov. Sincerely, JUDY BLOOM Digitally signed by JUDY BLOOM Date: 2023.11.14 12:35:05 -07'00' Judy Bloom, Supervisor Drinking Water Section B Water Division cc: Philip Wong, Civil Engineer Bridger-Teton philip.wong@usda.gov 2