Health effects of coal ash

Coal ash is produced at coal-fired power plants. Coal is pulverized and then burned to generate electricity. The particles that remain after burning coal are called coal ash, principally consisting of fly ash and bottom ash. Other coal combustion by-products are boiler slag, flue gas desulfurization gypsum, and other kinds of flue gas desulfurization residues. Coal ash obtained from the combustion of bituminous coal is constituted principally of aluminum oxide (Al2O3), calcium oxide (CaO) and silicon dioxide (SiO2). Such constituents that are found at various concentrations in coal ash are arsenic, cadmium, chromium, cobalt, copper, lead, lithium, mercury, molybdenum, selenium, thallium and uranium. In the United States approximately 110 million tons of coal ash were generated in 2012. == Occupational health concerns ==

Coal ash contains many toxic substances that may affect human health, if people are exposed to them above a certain concentration in the form of particulate matter. So it is necessary to avoid situations in which employees working in coal-fired power plants or public members living close to coal ash landfills will be exposed to high coal ash dust concentrations. == Health effects of toxic pollutants ==

Different constituents can be found in coal ash. Lead: The direct exposure to lead can cause major damage to the nervous system. Both low levels and high levels of lead exposure can cause harm to the human body. Ultimately, exposure of arsenic over a long period of time can cause mortality. Boron: When coal ash dust is inhaled, the exposure of boron can cause discomfort in the throat, nose and eye. As a result, short-term molybdenum exposure can cause an increase of wheezing and coughing. Furthermore, chronic exposure of molybdenum can cause loss of appetite, tiredness, headaches and muscle soreness. Thallium: The exposure of thallium in coal ash dust can cause peripheral neuropathy when inhaled. Furthermore, when coal ash is ingested, thallium exposure can cause diarrhea and vomiting. In addition, thallium exposure is also associated with heart, liver, lung and kidney complications. Silica: When silica is inhaled from coal ash dust, fetal lung disease or silicosis can develop. Furthermore, chronic exposure of silica can cause lung cancer. In addition, exposure to silica over a period of time can cause loss of appetite, poor oxygen circulation, breathing complications and fever. == Coal ash reuse ==

Reuse of coal ash may benefit the environment by reducing the production of greenhouse gas and reducing the need to use virgin materials. In addition, when coal ash is recycled, costs related to coal ash disposal sites are avoided. There are two forms of coal ash recycling: “encapsulated” and “unencapsulated." When coal ash is bound to other materials it is encapsulated. For example, coal ash can be reused in making concrete, bricks and wallboards. On the other hand, unencapsulated use of coal ash is when the ash is not bound to other materials (loose particulate or sludge form). An example of unencapsulated coal ash is distributing the ash on icy roads in the winter. Even though reusing coal ash minimizes health effects in humans, health problems can still occur when coal ash is recycled. Specifically, workers drilling or cutting encapsulated coal ash increase their risk of inhaling coal ash dust. In addition, when unencapsulated coal ash is scattered on snowy streets in the winter, the loose ash can come in contact with ditches on the side of the road. As a result, the toxins from coal ash can leach into surface water bodies as well as groundwater, which may be drinking water sources. Therefore, both forms of recycled coal ash (encapsulated and unencapsulated) can cause serious health issues in humans. == Coal ash waste regulations ==

In the United States, when coal ash is disposed into surface impoundments and landfills, the ash is regulated as a "Special Waste" (i.e., non-hazardous) under the Resource Conservation and Recovery Act (RCRA). EPA published a Coal Combustion Residuals (CCR) regulation in 2015. The agency continued to classify coal ash as non-hazardous (thereby avoiding strict permitting requirements under RCRA Subtitle C), but with new restrictions: • Existing ash ponds that are contaminating groundwater must stop receiving CCR, and close or retrofit with a liner. • Existing ash ponds and landfills must comply with structural and location restrictions, where applicable, or close. • A pond no longer receiving CCR is still subject to all regulations unless it is dewatered and covered by 2018. • New ponds and landfills must include a geomembrane liner over a layer of compacted soil. In 2016, the United States Court of Appeals for the District of Columbia Circuit vacated the "early closure" provisions in the regulation at 40 CFR 257.100. EPA then extended the compliance date for inactive ponds that attempted to utilize the early closure provisions. In 2018, at the request of industry, EPA extended the compliance date for unlined ash ponds from 2019 to 2020, and provided more flexibility to state agencies in determining compliance with standards. The 2018 regulation was challenged in litigation and remanded by the court to EPA for further revision. The court ruled that EPA failed to adequately address the problems with unlined ponds, many of which continue to leak into groundwater. In 2019, the court agreed to a voluntary remand while allowing the 2020 compliance deadline for unlined ponds to stay in effect, pending further rulemaking. EPA published a proposed rule on August 14, 2019 that would use location-based criteria, rather than a numerical threshold (i.e. impoundment or landfill size) that would require an operator to demonstrate minimal environmental impact so that a site could remain in operation. In response to litigation on the 2015 regulation, EPA published a final RCRA regulation on August 28, 2020 requiring all unlined ash ponds to retrofit with liners or close by April 11, 2021. Some facilities may apply to obtain additional time—up to 2028—to find alternatives for managing ash wastes before closing their surface impoundments. == References ==