In a split decision on May 9, 2023, the U.S. Court of Appeals for the District of Columbia ordered the United States Environmental Protection Agency (EPA) to regulate the chemical perchlorate.1 EPA determined in 2011 that perchlorate should be regulated, but under the Trump Administration withdrew that determination in 2020 based on a new analysis. After its own analysis, the Biden Administration subsequently supported that withdrawal in a 2022 publication, however the Court found that the Safe Drinking Water Act requires EPA to regulate perchlorate as a result of its 2011 determination, regardless of what the best available science shows today.
The following statement may be attributed to Bill Romanelli, spokesperson for the Perchlorate Information Bureau:
“It’s notable the Court was divided on whether or not EPA was actually required to regulate perchlorate. The key quote comes from Justice Pan, who articulated it perfectly: ‘The majority’s interpretation gives the agency no choice but to impose a pointless burden on water systems to test for a substance that the agency does not even think should be regulated. Congress could not have intended such an illogical result.’
“The fact that Justice Pan took issue with EPA’s comments related to IQ, unfortunately, demonstrates a fundamental aspect of perchlorate science that has been missed by many. Perchlorate has a very well documented, scientifically established “No Observed Effect Level” equivalent to 245 parts per billion in water, and only one public water system in the US has ever measured perchlorate in excess of that level.2
Further, in answer to Justice Pan’s concerns about the data on perchlorate occurrence, evidence from separate studies by EPA (2020) and Corey, et al. (2017) actually show perchlorate concentrations in drinking water across the U.S. are decreasing.
1 NRDC v. EPA, Case 20-1335 (Document # 1998466), May 9, 2023
2 US EPA Perchlorate Occurrence and Exposure (Updated UCMR 1 Data Set). The only water system above 90 ppb was in Puerto Rico with a value of 420 ppb at the time. EPA stated: EPA contacted the Puerto Rico Aqueduct and Sewer Authority (PRASA) in January 2019. PRASA personnel indicated that no updated monitoring data for perchlorate is available. PRASA personnel stated that the Utuado water system was significantly impacted by hurricane Maria and monitoring records from years prior to 2017 were lost.
In nearly 70 years of scientific study, there has been no evidence that levels of perchlorate found in drinking water – where it is found – have any adverse effect.
More information is available online from the Perchlorate Information Bureau.