Public healthAre tighter EPA controls on mercury pollution worth it?
Over 300,000 babies every year are born in the United States with levels of mercury that put them at risk of neurological and developmental problems. How much would you be willing to spend to reduce this number? This might seem like an abstract question, but the judgments regulators make on this question can determine whether or not a proposed regulation survives challenges in court. This was a key question addressed when the Mercury and Air Toxics Standards (MATS) was reviewed by the Supreme Court. In a 5-4 vote in June 2015, the Supreme Court held that the EPA should have considered costs when deciding to regulate mercury. Research suggests that including a larger set of health effects of high levels of mercury – namely, both IQ and heart attacks – and the impact on specific populations could lead to mercury-related benefits estimates that are orders of magnitude larger than those reported by the EPA. Regardless of the approach used to weigh advantages and disadvantages of policy, the research is now clear: the benefits of MATS are substantial.
Over 300,000 babies every year are born in the United States with levels of mercury that put them at risk of neurological and developmental problems. How much would you be willing to spend to reduce this number?
This might seem like an abstract question, but the judgments regulators make on this question can determine whether or not a proposed regulation survives challenges in court.
Regulation is an issue on the presidential campaign trail as well, with a number of candidates arguing that tighter environmental rules will strangle the economy and deliver few benefits.
One regulation at stake is an Environmental Protection Agency (EPA) proposal to control mercury emissions from power plants under the Clean Air Act, through the Mercury and Air Toxics Standards (MATS) issued in 2013, which remains in effect after a Supreme Court ruling last year challenged aspects of the decision to regulate.
We’ve done research to quantify the economic impacts from better public health of proposed mercury rules and found the benefits are substantial – on the order of billions of dollars per year, with significant improvements for at-risk populations.
Supreme Court versus EPA
Mercury is a global environmental pollutant. In its most toxic form, methylmercury, it bioaccumulates in fish, posing risks of health effects such as cognitive and behavioral impacts and cardiovascular damage in people who consume fish.
Mercury that contaminates fish comes from ongoing as well as historical human activities – primarily, burning coal in power plants as well as mining.
Mercury can travel long distances through the air before it deposits in aquatic ecosystems, so mercury emitted anywhere in the world can reach the U.S. This means that U.S. fish consumers are affected by both domestic mercury emissions, which contaminate nearby waterways, and global sources, which can travel across borders to affect oceans and watersheds worldwide.
In the United States, many sources of mercury emissions have already been regulated, and domestic emissions have decreased substantially in the past few decades. The largest remaining domestic source is emission from coal-fired power generation. Worldwide, mercury is the subject of a recent global environmental treaty, named the Minamata Convention after a city in Japan where methylmercury poisoning was first identified decades ago.
