EPA contracted helicopter flyovers of a portion of the Permian Basin from August 25 through September 12, 2020, to assess emission sources using Optical Gas Imaging (OGI) technology. On August 30th and September 10th, 2020, EPA flew over sites identified as Rio-owned facilities. On December 14, 2020, EPA sent a letter informing Rio of potentially unauthorized emissions from facilities that EPA believed were owned/operated by Rio, along with OGI video captures for the facilities. For each facility, EPA asked Rio to verify ownership, provide current site-specific permit information, and take any necessary corrective action to address unauthorized hydrocarbon emissions.
EPA considered information provided by Rio to determine whether violations occurred at the Facilities, and on February 2, 2022, sent a Notice of Violation and Opportunity to Confer (NOVOC) letter to inform Rio of the violations of the Texas State Implementation Plan (SIP), specifically: 30 Tex. Admin. Code106.4(c), 106.6(b) and (c), 106.352(l)(1), 106.512(1), 106.352(1)(5), and 106.110(a).