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Pollution

Fireworks produce smoke and dust that may contain residues of heavy metals, sulfur-coal compounds and some low concentration toxic chemicals. These by-products of fireworks combustion will vary depending on the mix of ingredients of a particular firework. (The color green, for instance, may be produced by adding the various compounds and salts of barium, some of which are toxic, and some of which are not.) Some fishers have noticed and reported to environmental authorities that firework residues can hurt fish and other water-life because some may contain toxic compounds (such as antimony sulfide or arsenic). This is a subject of much debate due to the fact that large-scale pollution from other sources makes it difficult to measure the amount of pollution that comes specifically from fireworks. The possible toxicity of any fallout may also be affected by the amount of black powder used, type of oxidizer, colors produced and launch method.

Perchlorate salts, when in solid form, dissolve and move rapidly in groundwater and surface water. Even in low concentrations in drinking water supplies, perchlorate ions are known to inhibit the uptake of iodine by the thyroid gland. As of 2010, there are no federal drinking water standards for perchlorates in the United States, but the US Environmental Protection Agency has studied the impacts of perchlorates on the environment as well as drinking water.

Several U.S. states have enacted drinking water standard for perchlorates, including Massachusetts in 2006. California's legislature enacted AB 826, the Perchlorate Contamination Prevention Act of 2003, requiring California's Department of Toxic Substance Control (DTSC) to adopt regulations specifying best management practices for perchlorate-containing substances. The Perchlorate Best Management Practices were adopted on 31 December 2005 and became operative on 1 July 2006. California issued drinking water standards in 2007. Several other states, including Arizona, Maryland, Nevada, New Mexico, New York, and Texas have established non-enforceable, advisory levels for perchlorates.

The courts have also taken action with regard to perchlorate contamination. For example, in 2003, a federal district court in California found that Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) applied because perchlorate is ignitable and therefore a "characteristic" hazardous waste.

Pollutants from fireworks raise concerns because of potential health risks associated with the products of combustion during the liquid phase and the solid phase after they have cooled as well as the gases produced, particularly the carbon monoxide and carbon dioxide. For persons with asthma or other respiratory conditions, the smoke from fireworks may aggravate existing health problems.

Pollution is also a concern because fireworks often contain heavy metals as source of color. However, gunpowder smoke and the solid residues are basic, and as such the cumulative effect of fireworks on acid rain is uncertain. What is not disputed is that most consumer fireworks leave behind a considerable amount of solid debris, including both readily biodegradable components as well as nondegradable plastic items. Concerns over pollution, consumer safety, and debris have restricted the sale and use of consumer fireworks in many countries. Professional displays, on the other hand, remain popular around the world.

Others argue that alleged concern over pollution from fireworks constitutes a red herring, since the amount of contamination from fireworks is minuscule in comparison to emissions from sources such as the burning of fossil fuels. In the US, some states and local governments restrict the use of fireworks in accordance with the Clean Air Act which allows laws relating to the prevention and control of outdoor air pollution to be enacted.

Some companies within the U.S. fireworks industry claim they are working with Chinese manufacturers to reduce and ultimately hope to eliminate of the pollutant perchlorate.