Land Disposal
Facilities report the quantities of TRI chemical waste disposed of in landfills, underground injection wells, surface impoundments, and other types of containment. Land disposal of chemicals is often regulated by EPA under the Resource Conservation and Recovery Act (RCRA). RCRA design standards for hazardous waste landfills and surface impoundments include double liners, leachate collection and removal systems, and leak detection systems. Operators of these disposal units must also comply with RCRA inspection and monitoring requirements.
This graph shows the 10-year trend in on-site land disposal of TRI chemicals. The metal mining sector accounted for most of this disposal.
What is underground injection?
Underground injection involves placing fluids underground in porous formations through wells. EPA regulates underground injection through its Underground Injection Control Program under the Safe Drinking Water Act.
What is a surface impoundment?
Surface impoundments are natural or artificial depressions, excavations, or diked areas used to hold liquid waste. Construction of surface impoundments must follow criteria including having a double liner and leak detection system. Surface impoundments containing hazardous waste are regulated through the Resource Conservation and Recovery Act.
From 2013 to 2022:
- On-site land disposal has fluctuated over the last ten years, driven by year-to-year changes from metal mines.
- The "All Other Land Disposal" category in the figure includes spills and leaks to land, waste rock piles at metal mines, and application of waste to land (such as in agricultural fertilizer).
From 2021 to 2022:
- Land releases increased by 41 million pounds (2%).
- The increase in land disposal was due to the expansion of TRI reporting requirements to cover all natural gas processing facilities as of 2022. Facilities in this sector managed most of their releases through underground injection.
Land releases from metal mines:
In 2022, the metal mining sector accounted for 68% of land disposal quantities. Select the “Land Disposal, Excluding Metal Mining” button to view the land disposal trend without data from metal mines.
- The TRI chemicals disposed to land by metal mines in 2022 were primarily lead (32%), zinc (28%), and arsenic (16%).
- Metal mining facilities typically handle large volumes of material. Mines often note that changes in the chemical composition of extracted ore can result in large fluctuations in quantities of waste managed. In some cases, small changes in the ore’s composition can impact whether TRI chemicals in ore qualify for a concentration-based exemption from TRI reporting in one year but not in the next year or vice versa.
- Regulations require that waste rock, which contains TRI chemicals, be placed in engineered piles, and may also require that waste rock piles, tailings impoundments, and heap leach pads be stabilized and re-vegetated to provide for productive post-mining land use.
- For more information on the mining industry, see the Metal Mining sector profile and the "Explore a Metal Mine" webpage.
This graph shows the 10-year trend in on-site land disposal, excluding quantities reported by the metal mining sector. The metal mining sector accounts for about 70% of the quantities of TRI chemicals disposed of to land in most years.
From 2013 to 2022:
- Total on-site land disposal for all industries other than metal mining was relatively steady from 2013 to 2018.
- Since 2018, the decrease in land disposal for industries other than metal mining was driven by reduced land disposal by facilities in the primary metal and chemical manufacturing sectors.
In 2022:
- Excluding the quantities of TRI chemicals disposed of to land by metal mines, the chemicals disposed of on site to land in the largest quantities were: barium (15%), manganese (11%), hydrogen sulfide (10%), and zinc (8%).
- Excluding metal mines, most on-site land disposal quantities were reported by the chemical manufacturing, hazardous waste management, electric utilities, and primary metals sectors.
- The natural gas processing sector reported 72 million pounds of land disposal, most of which was hydrogen sulfide disposed of by underground injection.
This page was published in March 2024 and uses the 2022 TRI National Analysis dataset made public in TRI Explorer in October 2023.