Aerosols
Much of the concern about using aerosols in products like deodorants and hairsprays comes from the use of chlorofluorocarbons, or CFCs. First developed in the late 1920s, CFCs became widely used as coolants for refrigerators and air conditioners, cleaning agents for electronics, and propellants for aerosols. CFCs had many advantages: they had low toxicity levels, they were nonflammable, and they did not react with other chemicals or decay. Their longevity would prove to be damaging to the environment, however. In the 1970s, scientists discovered that CFCs were eating away at the ozone layer, damaging its ability to protect Earth from the sun's harmful rays.
CFCs also trap heat in the atmosphere and contribute to global warming. Because of these concerns, the EPA banned the use of CFCs in aerosols in 1978. CFCs are being phased out under the Montreal Protocol, administered by the United Nations Environment Programme (UNEP). As part of the agreement, industrialized nations were required to stop using CFCs by January 1, 1996, with developing nations following suit by the year 2010. Today, 191 nations abide by the Montreal Protocol. The UNEP lists five nations that have yet to ratify the treaty: Iraq and Timor-Leste in Asia, and Andoro, San Marino, and the Holy See, otherwise known as Vatican City, in Europe.
The protocol does afford exemptions for the use of CFCs in metered-dose inhalers, for use in the Space Shuttle and Titan Rocket programs, and for use in laboratories.
If you are concerned with the chemicals present in your favorite product, you can check out the material-safety data sheets (MSDS) at www.householdproducts.nlm.nih.gov.
The MSDS for hair spray and other aerosols list that these items should be disposed of as hazardous waste because of their RCRA D001 designation. This designation simply means that the products are ignitable. There have been reports of aerosol cans exploding so violently inside hot cars that they became embedded in car seats and broke car windows.
Aerosols do produce a mist of fine particulate matter; that's one of the qualities that allows an even and light distribution on your hair or under your arm. Studies performed on hair stylists have not indicated any propensity to life-threatening diseases, but they were susceptible to skin irritations and minor breathing problems. Aerosols should be used in well-ventilated areas to avoid any health risks.
Aerosol cans are made of steel that can be recycled. They should be emptied before they are placed in the recycle bin to avoid explosion.
