A burn pit refers to an area in military sites devoted to open-air combustion of trash. The phrase was first used to refer to the common way of getting rid of waste at the U.S. military sites in Iraq and Afghanistan. Due to modern waste at and around these sites containing significant amounts of plastic and other material which may emit toxic aerial compounds and particulates when burned, the burn pits were heavily criticized and resulted in a suit by veterans. Global environmental consciousness has especially criticized these instances of large-scale burn pit operation.
The Iraq and Afghanistan U.S. military burn pit operation scandal
In 2010, a large-scale burn pit operation in Iraq and Afghanistan, allegedly operated by the U.S. military or its contractors such as KBR, was reported to have allowed the operation of the burn pits for long periods of time, burning many tons of assorted waste. Active duty personnel reported respiratory difficulties and headaches in some cases while some veterans made disability claims based on respiratory system symptoms allegedly derived from the burn pits. A Minnesota mother, Amie Muller, was a victim of the exposure and her senator, Amy Klobuchar (MN-DFL), carried a bill called the “Helping Vets Exposed to Burn Pits Act” that was passed and signed into law by President Donald Trump (as H.R. 5895) on September 21, 2018. Through 2019, it will provide $5 million for burn pit research, education and evaluation of the exposure of other U.S. service members and veterans to burn pits and toxic airborne chemicals.
The materials burned and combustion products
In the Iraq and Afghanistan incidents of burn pit operation involving the US military, it was reported that every type of waste was burned, including: plastics, batteries, appliances, medicine, dead animals, even human body parts with jet fuel being used as an accelerant. Clouds of black smoke resulted. According to an Air Force fact sheet, "Burning solid wastes in an open pit generates numerous pollutants. These pollutants include dioxins, particulate matter, polycyclic aromatic hydrocarbons, volatile organic compounds, carbon monoxide, hexachlorobenzene, and ash. Highly toxic dioxins, produced in small amounts in almost all burning processes, can be produced in elevated levels with increased combustion of plastic waste (such as discarded drinking water bottles) and if the combustion is not at high incinerator temperatures. Inefficient combustion of medical or latrine wastes can emit disease-laden aerosols."
Joint Base Balad, the largest U.S. base in Iraq had a burn pit operation as late as the summer of 2008 burning 147 tons of waste per day when the Army Times published a major story about it and about health concerns. An Air Force spokesman speaking for the 609th Combined Air and Space Operations Center Southwest Asia vigorously contested allegations of health effects and emphasized mitigation efforts. In Afghanistan, at its peak, more than 400 tons of trash were disposed using burn pits a day.
"Within a mile of BIAP (Baghdad International Airport) and also within a mile of camps Cropper and Stryker was one of these burn pits. The ash rained down on us like snowflakes - not only on US troops, but also Iraqi detainees and Iraqi correctional officers (aka ICO's). There were flakes of ash the size of half a sheet of notebook paper. That installation was perpetually downwind of one particular burn pit, and while this wasn't an everyday occurrence, during winter of 2007 into 2008 it did happen often. This is not to speak for the frequency of the burnings, but the ash literally came down like snowfall over the facility."
The burn pits were allegedly adopted as a temporary measure but remained open long after alternative methods of disposal such as incineration were available. After some years the American military did adopt other methods. 
In November 2009, at the request of the Veteran's Administration (VA), the National Academy of Sciences Institute of Medicine (IOM) began an 18-month study to determine the long-term health effects of exposure to the burn pits in Iraq and Afghanistan.
At the request of the VA and the Department of Defense, the Board on the Health of Select Populations of the Institute of Medicine formed the Committee on Long-term Health Consequences of Exposure to Burn Pits in Iraq and Afghanistan which held its first meeting February 23, 2010 - February 24, 2010 in Washington, D.C.
In 2011, the Institute of Medicine reviewed the scientific literature related to the possibility of adverse long-term health effects of open burn pits. The report, Long-Term Health Consequences of Exposure to Burn Pits in Iraq and Afghanistan noted U.S. Department of Defense air quality monitoring data measured levels of particulate matter (PM) higher than generally considered safe by U.S. regulatory agencies. It also cited work linking high PM levels to cardiopulmonary effects, particularly in individuals at increased risk due to pre-existing conditions such as asthma and emphysema. They concluded that there is only limited evidence suggestive "of an association between exposure to combustion products and reduced pulmonary function in these populations."
If there is sufficient evidence of a connection between exposure to burn pits and subsequent illness and disability, it might serve as the basis for congressional enactment of a "presumption of service connection" similar to that in place for exposure to Agent Orange.
The VA Airborne Hazards and Open Burn Pit Registry established in 2014 of to gather information about Veterans and Servicemembers collected through a questionnaire. Operation Enduring Freedom/Operation Iraqi Freedom/Operation New Dawn (OEF/OIF/OND) or 1990-1991 Gulf War Veterans and Servicemembers can use the registry questionnaire to report exposures to airborne hazards (such as smoke from burn pits, oil-well fires, or pollution during deployment), as well as other exposures and health concerns.
Reports on the registry data:
1. Report on Data from the Airborne Hazards and Open Burn Pit (AH&OBP) Registry, June 2015 - Between April 25, 2014, and December 31, 2014, nearly thirty thousand Veterans and Active Duty Servicemembers filled out the registry survey. This report highlights health conditions and physical limitations experienced by burn pit registry participants.
- The most common doctor-diagnosed health problems reported were insomnia and neurological problems.
- Other commonly diagnosed health problems reported include allergies, high blood pressure, and lung disease like emphysema, chronic bronchitis, and asthma.
- It is important to remember that Registry findings alone can't tell if exposure to burn pits, dust storms, or other hazards caused these health conditions.
Proposed Health Tracking
US Army veteran and University of Pennsylvania graduate student, Chad Baer, has vocally asserted that claims of inclusive results are due to faulty research design. Baer was selected as a SVA/VFW Legislative Fellow in 2019, and traveled to Capitol Hill to advocate for a predictive analytics model. Baer has asserted that technological advances have made longitudinal studies of all veterans feasible, except that this is not possible so long as the Department of Defense refuses to give VA researchers more complete data. The data in question would be the personnel data that would allow the VA to establish "clusters", based on items such as physical location, job specialties, or other relevant data points.  
- "Burn Pits". publichealth.va.gov. U.S. Department of Veterans Affairs. 2011. Retrieved 2016-07-13.
- "Veterans Sound Alarm Over Burn-Pit Exposure" article by James Risen in The New York Times August 6, 2010, accessed August 7, 2010
- "Burn pit at Balad raises health concerns: Troops say chemicals and medical waste burned at base are making them sick, but officials deny risk" article by Kelly Kennedy in Army Times Oct 29, 2008, accessed August 7, 2010
- Vlahos, Kelley Beaucar (14 February 2015). "'Indefensible': Report reveals extent of 'burn pit' pollution inhaled by US troops in Afghanistan". Fox News. Retrieved 21 February 2015.
- First Meeting of the Committee on the Long-Term Health Consequences of Exposure to Burn Pits in Iraq and Afghanistan Keck Center of the National Academies, accessed August 8, 2010
- Long-Term Health Consequences of Exposure to Burn Pits in Iraq and Afghanistan, accessed July 9, 2015 Archived May 31, 2014, at the Wayback Machine
- Airborne Hazards and Open Burn Pit Registry, accessed July 9, 2015
- "Burn pits at US bases in Iraq, Afghanistan blamed for veterans' illnesses". Stars and Stripes. Retrieved 2018-09-24.
- Department of Veterans Affairs, Public Health, VA's Airborne Hazards and Open Burn Pit Registry webpage
- VA Airborne Hazards and Open Burn Pit Registry Video
- "Report: Army making toxic mess in war zones" article by Kelly Kennedy in Military Times Oct 3, 2008
- David E. Mosher, Beth E. Lachman, Michael D. Greenberg, Tiffany Nichols, Brian Rosen, Henry H. Willis, Green Warriors: Army Environmental Considerations for Contingency Operations from Planning through Post-Conflict, Rand Corporation (2008), trade paperback, 252 pages, ISBN 9780833043184
- Environmental Health Surveillance Registries (EHSR) website - U.S. Department of Defense (DoD) information page for VA Burn Pit Registry
- Military Burn Pits: the New Agent Orange? by Mary Anne Mercer et al, Huffington Post. http://www.huffingtonpost.com/news/burn-pits/
- American Public Health Association policy statement, 2015: "Cleanup of U.S. Military Burn Pits in Iraq and Afghanistan" https://www.apha.org/policies-and-advocacy/public-health-policy-statements/policy-database/2015/12/16/08/56/cleanup-of-us-military-burn-pits-in-iraq-and-afghanistan
- Al-Jazeera interview with U.S. veteran and experts (1 August 2017): https://www.youtube.com/watch?v=N9Wj1us36dk