Formaldehyde is useful because of the wide range of chemical reactions in which it can participate. It is a strong reducing agent, it water soluble (formalin solution) and most importantly it is an alkylating agent and binds amine groups, and aromatic rings. These last properties are what makes formaldehyde useful in healthcare. Formaldehyde solution (formalin) is used as a fixative because it can cross link proteins and so fix tissue samples. It does the same thing in living organisms and so formaldehyde is strongly antimicrobial finding use as a disinfectant and sterilant (e.g. low temperature steam formaldehyde sterilization)
As with any chemical sterilant, formaldehyde poses significant risks to anyone exposed to it. Formaldehyde is a known carcinogen and causes cancer of the nasopharynx & sinonasal cancer and leukaemia. (IARC) and National Toxicology Program). It is also a sensitizer and a primary irritant [ATSDR].
These dangers are well known and OSHA has promulgated a standard for formaldehyde (29 CFR 1910.1048) and has set permissible exposure limits of 0.75 ppm (8 Hour time weighted average (TWA), and 2 ppm as a 15 minute TWA short term exposure level (STEL).
Formaldehyde is a very useful chemical, but it is often used in environments that are not set-up to handle chemical exposures. For example formaldehyde is often used in hair straightening formulations (similar chemical mechanism to the tissue fixative) and in the last couple years OSHA has targetted beauty salons, issued a press release a hazard alert and even created a website dedicated to the dangers of formaldehyde exposure in addition to citing them for violations of OSHA standards. However, most beauty salons have neither the equipment nor the training to protect their workers to the levels required by the OSHA standard.
The product manufacturers have been of marginal help, sometimes inadvertently leaving the formaldehyde off the product label ingredients, claiming that the levels are so low as to be safe or using one of the other chemical names for formaldehyde such as methylene glycol that is less easily recognized by those with limited chemical training. A much safer approach for both the salon workers and of course their customers would be to eliminate all formaldehyde from these applications.
Formaldehyde solution was widely used as a disinfectant and sterilant in healthcare, but in the US it has largely been replaced by glutaraldehyde as a liquid sterilant/high level disinfectant. Low temperature steam formaldehyde is still widely used in European and other countries in dedicated LTSF sterilizers. In the US formaldehyde is primarily used in health care as a tissue preservative and as a major component of embalming fluids.
Formaldehyde can be used safely provided that adequate safety precautions are taken. Employers using formaldehyde must provide the OSHA required Hazard Communication training for all workers using hazardous chemicals (29 CFR 1910.1200) as well as training on the formaldehyde specific standard.
Employers must ensure that their people are not exposed to formaldehyde concentrations over the OSHA PELs. Employers who use formaldehyde can do this by use of adequate engineering controls to prevent exposure, continuous gas monitors for formaldehyde to ensure that the other safety devices are sufficiently protective and provide warning to workers in something fails, suitable personal protective equipment and training on how to handle formaldehyde safety and what to do it things go wrong. These are similar to the requirements as for other sterilant and high level disinfectant chemicals such as ethylene oxide, hydrogen peroxide, peracetic acid, o-phthalaldehyde and glutaraldehyde.