Formaldehyde occurs naturally in the environment and is produced in large scale around the world for use as adhesives and binders for wood products (such as plywood), pulp, paper and other manufactured products and in flame retardants. As a reactive and inexpensive chemical it is a building block in many manufacturing processes, during which formaldehyde may be given off to react with other substances in the environment and cause short-term exposure, respiratory problems, and from long-term exposure, damage to the immune system Formaldehyde is a potent sensitizing agent and a carcinogen with links to certain cancers. Small concentrations may cause allergic reaction and have particularly bad effects on people suffering from respiratory complaints such as asthma.
A World Health Organization panel upgraded its assessment of the danger of formaldehyde in 2004, declaring for the first time that the chemical is "carcinogenic to humans."
Formaldehyde is a byproduct of many combustion processes, including that of natural gas and petroleum, so it is a component of car exhausts. It is also found in building materials, urea-formaldehyde foam insulation, resin treated textiles, and wood particle products glued together with formaldehyde resins. Sweden, Germany, Denmark, Belgium and the USSR have set maximum formaldehyde standards for buildings.
Formaldehyde is found in mattresses, either as a byproduct of other chemicals or in glue used to bind fibers together; and most bed sheets are sprayed with formaldehyde to reduce wrinkling. Formaldehyde vapour is a common smell in new buildings, but the "offgassing" continues even when the smell has disappeared.
A Harvard School of Public Health study found that men who work with formaldehyde products had triple the risk of ALS (Lou Gehrig's Disease).