Formaldehyde is a colourless, flammable gas with a strong, pungent odour. It is sold mainly as an aqueous solution called formalin, which is 37% to 50% formaldehyde by weight. Formaldehyde is used to produce synthetic resins such as urea- and phenol-formaldehyde resins – used primarily as adhesives when making particle-board, fibreboard, and plywood. Embalming fluids contain formaldehyde and its use is common in pathology labs.
The International Agency for Research on Cancer (IARC) has recently declared formaldehyde a human carcinogen.
The first signs or symptoms (noticed at concentrations between 0.1-5 ppm) are burning of the eyes, tearing and irritation to the upper respiratory passages. Higher exposures (10-20 ppm) may produce coughing, tightening in the chest, a sense of pressure in the head, and palpitation of the heart. Exposures at 50-100 ppm and above can cause serious injury such as collection of fluid in the lungs, inflammation of the lungs (pneumonitis), or death.
Dermatitis due to formaldehyde solutions or formaldehyde-containing resins is well recognised. After a few days exposure, a worker may develop a sudden inflammatory (eczematous) reaction of the skin of the eyelids, face, neck, scrotum, and flexor surfaces of the arms. An eczematous reaction may also appear on the fingers, back of the hands, wrists, forearms, and parts of the body that are exposed to the rubbing of clothing. This sometimes occurs only after years of repeated exposure.
Minimising employee exposure
Formaldehyde should be handled in the workplace as an occupational carcinogen. Exposure should be limited to as few employees as possible, and workplace exposure levels minimised.
Initial and routine employee exposure surveys should be made to determine the extent of employee exposure and to ensure that controls are effective.
Controlling employee exposure
There are four basic methods of limiting employee exposure to formaldehyde.
1. Product substitution
The substitution of an alternative (safe) material with a lower potential risk is an important method for reducing exposure.
2. Contaminant controls
The most effective control is at the source of contamination by enclosure of the operation and/or use of local exhaust ventilation.
3. Employee isolation
If feasible, employees may be isolated from direct contact with the work environment by the use of automated equipment operated by personnel in a closed control booth or room.
4. Personal protective equipment (PPE)
The use of PPE, which may include respirators, goggles, gloves, etc.: during the time period necessary to install or implement engineering or work practice controls in work situations in which engineering and work practice controls have proven ineffective:
- for maintenance
- for operations which require entry into tanks or closed vessels
- in emergencies.
Proper maintenance procedures, good housekeeping in the work area, and employee education are all vital aspects of a good control programme. Employees should be informed as to the nature of the hazard, its control, and appropriate personal hygiene procedures.
Health effects such as upper respiratory irritation or dermatitis should alert management that unacceptable exposure to formaldehyde is occurring. A medical surveillance programme should be made available that can evaluate these effects. In addition, skin protection should be stressed in the workplace to keep the number of new cases of dermatitis to a minimum.
These comments also apply to glutaraldehyde.