The US Environmental Protection Agency has announced it has withdrawn the legal justification for its Mercury and Air Toxics Standards, which was developed during the time of the Obama administration. A cost-benefit analysis between the costs of installing mercury-controlling technology and the public health benefits that such technology would bring – not just from reductions in mercury pollution but from other pollutants such as particulate matter as well – had been the basis of the justification. Under the Trump administration, however, the EPA has reassessed the justification, narrowing the benefits to include only those from a reduction in mercury emissions. The EPA’s new estimate is that the cost for complying with the standards would be US$7.4-9.6 billion (€6.8-8.9 billion) per year, compared to benefits of US$4-6 million (€3.7-5.5 million) per year, a full three orders of magnitude less. EPA Administrator Andrew Wheeler said of the reassessment that the “more transparent we are about the science behind our regulations, and the costs and the benefits behind our regulations, the more acceptance we will see across the board from the American public.” However, the EPA has not withdrawn MATS itself, and has said it will defend it in court, though by reassessing the legal justification, the agency has set itself up for defeat if challenged legally. Mr Wheeler also said that the reassessment foreshadows the EPA’s approach to future cost-benefit analysis and regulation. Former EPA administrator Gina McCarthy has called the reassessment “an absolute abomination”, while trade group Edison Electric Institute has said the move “introduces new uncertainty and risk for companies that still are recovering the costs for installing those control technologies”. Coal mining group The National Mining Association has welcomed the news.