The RCRA 8 metals are a group of eight toxic heavy metals regulated by the EPA (Environmental Protection Agency) under the authority of the Resource Conservation and Recovery Act (RCRA). Due to their toxicity, the metals pose significant health risks if ingested or absorbed and can lead to contamination of soil and groundwater if directly disposed of in landfills. For these reasons, waste contaminated with RCRA metals must be appropriately managed from “cradle to grave” to protect human health and the environment.
Even though they present a hazard, the metals—arsenic, barium, cadmium, chromium, lead, mercury, selenium, and silver—are helpful in various industrial and commercial products and applications. RCRA metals are found in batteries, electronics, paints, pesticides, pipes, industrial drill bits, pharmaceuticals, jewelry, disinfectants, rat poison, and more. Their wide use and potential danger make the proper handling, storage, transportation, and disposal of RCRA metal wastes vitally important.
EPA Characteristics of Hazardous Wastes
As stated, RCRA metals are hazardous due to their toxicity, one of four inherent characteristics the EPA uses to identify hazardous materials. A material’s ignitability, corrosivity, or reactivity are the other defining characteristics that classify waste as hazardous.
For safety and identification purposes when shipping, the EPA assigned alpha-numeric hazardous waste codes according to the waste’s characteristics. Code D001, for example, is for any ignitable or flammable waste. D002 is for types of corrosive wastes. D003 is for wastes that react violently or release poisonous gases upon exposure to air, water, light, or other materials. The last category codes D004–D043, identifies wastes by toxicity and is where the RCRA 8 metal listings are found.
The RCRA 8 Metals: Toxicity and Uses
1. Arsenic is a highly toxic and carcinogenic metalloid element. Found in small amounts in the Earth’s crust, it can be released into the environment through natural processes or human activities such as mining, smelting, and pesticide use. Arsenic can contaminate water, soil, and air, posing significant health risks to humans and wildlife. Its hazardous waste code is D004, with a designated allowable degree of concentration in waste of 5 ppm (parts per million).
2. Barium is a soft, silvery-white, odorless alkaline earth metal that, in its pure form, is toxic and can be hazardous to human health if ingested or inhaled, leading to gastrointestinal, cardiovascular, respiratory, and muscular issues. It can produce toxic or corrosive fumes when heated. Barium is used in various industrial applications, including oil and gas drilling, drill bits, medical imaging, fireworks, and in the production of fluorescent lighting and ceramic tiles. Its hazardous waste code is D005, with a regulated limit of 100 ppm.
3. Cadmium, waste code D006 with a regulated level of 1 ppm, is a soft, bluish-white, brittle, highly toxic metal. Exposure to cadmium has been linked to serious health problems, including an increased risk of lung and prostate cancer, as well as kidney damage and bone fractures. Additionally, it can cause developmental issues in children, highlighting the need for caution and proper handling of this highly toxic substance. It’s used in various industrial applications, including batteries, pigments, plastics, smelting, solar panels, and coatings.
4. Chromium is a lustrous, steel-gray metal extracted from chromite ores. It exists in two primary forms: trivalent chromium, which, in small quantities, is essential for human health, and hexavalent chromium, which is toxic and considered carcinogenic, especially when inhaled over time. Workers exposed to hexavalent chromium risk developing lung, nasal, and sinus cancer. Chromium is valued as the corrosion-resistant alloying element used in producing stainless steel. It’s also used in dyes, pigments, and chrome plating applications. Its EPA hazardous waste code is D007 and is regulated at five parts per million.
5. Lead is a common bluish-white metal used in various applications, including batteries, pipes, paint, and ammunition. It is also highly toxic and can cause a range of serious health problems, including neurological damage and developmental delays in children, reproductive problems and birth defects, and cardiovascular issues. Its code is D008, and its regulation level is five ppm.
6. Mercury is a heavy, silvery metal that occurs naturally in the environment. It is a potent neurotoxin that can cause serious health problems and damage the brain, kidneys, and nervous system. Prolonged exposure can also cause birth defects and other long-term health effects. The EPA hazardous waste code for mercury is D009, and its regulated level is 0.2 ppm.
7. Selenium is a naturally occurring element essential for human health in small amounts. However, excessive exposure to selenium can be toxic and cause damage to the nervous system, liver, and kidneys, leading to symptoms such as nausea, vomiting, and diarrhea. In severe cases, selenium poisoning can cause hair loss, skin lesions, and even death. Industrial applications include electronics, glass, pesticides, fungicides, rubber products, nutritional supplements, pharmaceuticals, antidandruff shampoos, and animal feed. Its waste code is D010, with a threshold of 1.0 ppm.
8. Silver’s waste code is D011, regulated at five ppm. The precious metal is used in various applications, including jewelry, photographs, electronics, brazing alloys and solders, and medical equipment. While it has antimicrobial properties and is essential for human health in small amounts, excessive exposure to silver can be toxic. Prolonged exposure can lead to a condition known as argyria, a bluish-gray skin discoloration. In rare cases, silver poisoning can also cause kidney damage and other health problems.
If your business or organization generates waste from using one or more of the RCRA 8 metals and needs help, assistance, or questions concerning their proper disposal, contact MLI Environmental. We are a trusted leader in New England’s hazardous waste disposal and management services. For more information, call MLI today.