An official website of the United States government.

This is not the current EPA website. To navigate to the current EPA website, please go to This website is historical material reflecting the EPA website as it existed on January 19, 2021. This website is no longer updated and links to external websites and some internal pages may not work. More information »

Toxics Release Inventory (TRI) Program

Aerospace Manufacturing Sector – Pollution Prevention (P2) Opportunities

The aerospace manufacturing sector—as defined by North American Industry Classification System (NAICS) code 3364—manufactures aircraft, spacecraft, and missiles, and rebuilds and overhauls aircraft and propulsion systems. For 2018, 278 facilities in the sector reported to the Toxics Release Inventory (TRI).

To track trends in pollution prevention (P2) and other sustainability practices in the aerospace manufacturing sector, the TRI Program analyzed the sector’s TRI data to characterize: 1) trends in the quantities of chemicals managed as waste, including releases to the environment; 2) top chemicals released by quantity; and 3) the types of practices used to prevent pollution.

TRI Waste Managed and Releases

For TRI reporting, the quantity of “waste managed” includes TRI chemical waste managed through recycling, energy recovery, treatment, or release to the environment. For details on quantities released, toggle to the Releases graph.


Source: U.S. EPA Toxics Release Inventory – 2018 National Analysis Dataset

  • Although the quantity of waste managed by the aerospace manufacturing sector has fluctuated, the quantity of TRI waste managed in 2018 was 3.8 million pounds (5%) less than in 2007, while the number of facilities in the sector reporting to TRI increased from 243 to 278 (14%).
  • Most of the sector’s TRI chemical waste (57%) was managed through recycling, driven by high recycling rates for metals and tetrachloroethylene. In 2018, only 5% of this sector’s waste was released into the environment.

In the context of TRI, a “release” of a chemical generally refers to a chemical that is emitted into the air, discharged to water, or disposed of in some type of land disposal unit. Releases are one part of a facility’s total waste management.


Sources: U.S. EPA Toxics Release Inventory – 2018 National Analysis Dataset

  • From 2007 to 2018, total releases by the aerospace manufacturing sector decreased by 29%. The decrease in releases was mainly driven by one facility which reported a 1.7 million pound decrease in hydrochloric acid releases to air from 2007 to 2018.
  • From 2007 to 2018, air releases by the aerospace manufacturing sector decreased by 2.3 million pounds (62%).


The following graph shows the chemicals released in the greatest quantities in 2007 and 2018.


Note: In this chart, metals are combined with their metal compounds, although metals and compounds of the same metal are listed separately on the TRI chemical list (e.g., nickel is listed separately from nickel compounds).

  • Releases decreased for most of the aerospace sector’s top TRI chemicals including hydrochloric acid, tetrachloroethylene (also called perchloroethylene), toluene, and nitric acid. However, releases increased for other chemicals such as chromium and nickel.
  • Decreases in releases of hydrochloric acid were driven by one facility (referenced above), which accounted for 97% of all hydrochloric acid released by the aerospace sector from 2007 through 2018.

Source Reduction Activities Reported to TRI

Reduced environmental releases of TRI-covered chemicals are driven in part by the implementation of source reduction activities. Each year, facilities report their newly implemented source reduction activities to TRI.


Source: U.S. EPA Toxics Release Inventory – 2018 National Analysis Dataset

  • For 2018, 8% of facilities in the aerospace manufacturing sector reported source reduction activities, compared to 6% of all facilities that reported to TRI.
    • In the aerospace sector, facilities commonly reported source reduction activities aimed at reducing the generation of scrap metal, and involving chromium, nickel, and copper, among other chemicals. Minimizing the generation of scrap metal is a source reduction practice because it reduces the quantity of waste generated at the source, while recycling of scrap metal is a waste management practice and is not considered source reduction.
    • Aerospace facilities reporting to TRI also implemented source reduction practices for non-metals. For example, one facility replaced an open-top batch degreaser with a closed loop vacuum degreaser equipped with a distillation column and a carbon adsorption drum on the exhaust line. The new unit significantly reduced trichloroethylene air emissions and waste.

Sustainability Activities in Aerospace Manufacturing

Additional examples of P2 opportunities in the aerospace sector identified from TRI, other EPA resources, and published articles include:

  • Reducing or eliminating hazardous organic solvents for degreasing. Aerospace manufacturers degrease metal parts in preparation for further finishing operations. Facilities operating in the sector might be using degreasing systems that use hazardous organic solvents such as trichloroethylene, a volatile organic compound that is characterized as a carcinogen. Certain aqueous cleaning systems or high-pressure steam cleaning may be effective degreasers and are considered acceptable alternatives by the Federal Aviation Administration.
    • Identifying alternatives to solvent degreasing To assist facilities in finding alternatives to solvent degreasers, EPA published a fact sheet, Case Studies on Safer Alternatives for Solvent Degreasing Applications. One case study featured an aircraft parts manufacturer that replaced several degreasers with aqueous and semi-aqueous cleaning systems.
  • Replacing traditional metal parts with plastic composites. Facilities have reported transitioning from copper to plastic composites for the manufacturing of certain aircraft parts, leading to reductions in the use and release of metals. This transition may be subject to customer approval, but some facilities have reported that demand for durable and lightweight equipment has increased interest in plastic composite materials.

For More Information

Top of Page