Significant sources of dioxins include uncontrolled burning of waste materials, industrial processes, and natural events like volcanic eruptions. The main sources can vary considerably by region. In the European Union, for example, rigorous pollution legislation limits industrial sources, while some developing nations have more lax laws and their factories produce large numbers of dioxins. These numbers also shift over time in response to regulation and changing industrial processes. The latest information for a given nation may be available through an environmental agency like the Environmental Protection Agency (EPA) in the United States.
Dioxins are chemical compounds known to be hazardous to human and environmental health. They are often produced as a byproduct of combustion but can also arise during some chemical processes. Part of the so-called “dirty dozen” of pollutants, their numbers are closely tracked worldwide because of their significant deleterious health effects. Government agencies concerned with health and pollution monitor concentrations and work on the development of better pollution controls to limit dioxin pollution.
For much of the 20th century, industrial processes were the primary sources of dioxins, including paper milling, incineration of industrial waste, chemical manufacturing, smelting, and refining. In response to rising dioxin levels associated with such activities, government agencies in many nations began cracking down on industrial pollution. The result was a significant decrease in dioxin emissions from these sources. Companies use a variety of pollution controls to limit overall production and control their dioxins to prevent contamination.
Burning of waste in uncontrolled settings like burn piles and backyard trash cans is a significant source of dioxins. Militaries also use burn barrels to dispose of waste while in the field, and these can add to the chemical burden. Natural processes like forest fires and volcanoes are also sources of dioxins; these are not controllable like industrial processes, and thus their pollution production as a percentage of overall sources of dioxins rose when industrial pollution started to drop.
The most common source of dioxin exposure for members of the general public is contaminated food. Careful regulation of the food supply along with regular testing can reduce but not eliminate risks. Certain occupations increase the risk of exposure because people are exposed to sources of dioxins like industrial processes that always produce at least some of these compounds, even with pollution controls. There are also reservoirs of dioxin contamination from eras when these compounds were widely produced that can be a significant source in some regions.