The Environmental Protection Agency (EPA) is announcing approval of a petition, from the Governor of the Virgin Islands (US VI), which seeks an exemption of the Clean Air Act (CAA) section 165(a) requirement to obtain a Prevention of Significant Deterioration (PSD) permit to construct prior to construction of a new gas turbine at the Virgin Islands Water and Power Authority (VIWAPA) St. Thomas facility. This exemption allows for construction, but not operation, of Unit 23 prior to issuance of a final PSD permit.