Information sheet: Formaldehyde Workplace Exposure Standard
The existing WES for formaldehyde is:
- Ceiling 1ppm
Two new WES for formaldehyde apply in addition to the existing WES-Ceiling:
- 0.5ppm WES-TWA (eight hour shifts)
- 0.33ppm WES-TWA (12 hour shifts)
The new WES will be implemented over a one-year period, commencing 13th December 2010. This means that employers and people in charge of workplaces have one year to make any changes necessary to ensure that no person is exposed to a concentration of formaldehyde exceeding the WES.
At this stage, these WES are guideline values until the Environmental Risk Management Authority has formally adopted them as controls under the Hazardous Substances and New Organisms Act 1996. At this point, the Authority will determine whether or not the WES should be guidelines only.
What is a Workplace Exposure Standard?
There are, in fact, a number of Workplace Exposure Standards (WES), designed for exposures over various time periods. In assigning the WES, defining a level that will achieve freedom from adverse effects is the major consideration.
In the case of formaldehyde, we use the following values:
- Time Weighted Average (TWA) – this means an average exposure of up to 0.5ppm (parts per million) formaldehyde over an eight-hour work day, or 0.33ppm over a 12-hour work day is permissable without experiencing poor health effects.
- Ceiling – the formaldehyde concentration should never exceed 1ppm during any part of the working day.
How are WES used in the workplace?
WES are used in relation to monitoring hazardous substances in the workplace environment. Special monitoring equipment is needed to measure airborne substances in the workplace (called air sampling). The equipment can cost a lot of money, and you need specialist training in how to take representative samples and make a correct analysis. In most workplaces, air sampling is carried out by occupational hygienists or people with similar qualifications and experience.
In all instances WES relate to exposure that has been measured by personal monitoring that uses methods that gather air samples from the workers’ breathing zones. The objective of personal monitoring is to assess the air a worker is breathing, as it is the workers’ exposure that the WES is concerned with.
Section 11 of the Health and Safety in Employment Act 1992 requires employers to provide the monitoring results to the workers concerned.
Why did the Department of Labour change the WES for formaldehyde?
The formaldehyde WES-TWA was added because:
- It is difficult to measure peak formaldehyde exposures using sampling methods commonly used in New Zealand, and
- the Ceiling limit effectively allowed a time-weighted average exposure of up to 0.99ppm over an eight-hour period. The current research shows that this level would not be an acceptable exposure over this period of time.
The addition of the TWAs means that more may have to be done in the workplace to reduce the level of worker exposure to this substance.
What are the health effects of formaldehyde exposure?
Formaldehyde can cause acute (short term) and chronic (long term) health effects. Acute effects may include sensory irritation of the eyes, nose and throat.
Formaldehyde is a skin irritant and a strong skin sensitiser. This means that once a person is sensitised, further exposure may cause intense responses, even at low concentrations.
Long term (chronic) exposure to formaldehyde may result in changes to the cells it regularly comes into contact with, such as inside the nose.
Formaldehyde is classified as a confirmed carcinogen, or cancer-causing agent, in New Zealand.
What occupations are linked to formaldehyde exposure?
Formaldehyde occurs naturally in the environment, and it is also produced (in low levels) in the body during metabolism. It is also produced during combustion.
Occupationally, people are usually exposed to formaldehyde by breathing in formaldehyde vapours, although formaldehyde is also present in formalin, a liquid preservative.
Formaldehyde is likely to be used in the following occupations:
- Laboratory work
- Mortuaries and funeral homes
- Urea-formaldehyde insulation production
- Pressed wood products including panel and board manufacturing
- Resin manufacturing
- Isocyanate paint and printing ink manufacturing
- Mould product casting
- Medical preservatives
- Motor vehicle manufacturing
- Textile manufacturing
- Natural gas and petroleum production.
What can be done to lower the amount of hazardous substances in the workplace air?
There are a number of ways to lower hazardous substances in the air, but it depends on a number of factors, including the work process, the equipment used and the work environment.
Here are some general examples of what could be done to lower worker exposure to hazardous substances:
- Substitute the hazardous substance for a less hazardous product;
- Install extraction ventilation to take the air containing the hazardous substance away from the workers;
- Enclose manufacturing processes so that all of the work involving the hazardous substance is conducted in a separate room or chamber that no-one normally works in; and
- ONLY as a last resort; or as an interim measure while long-term solutions are introduced: use personal protective clothing and equipment (PPE) to further reduce worker exposure.
Why can’t we just rely on PPE to protect us from harm?
The Health and Safety in Employment Act 1992 places duties on employers to eliminate all significant hazards in the workplace to ensure the safest working environment.
But in a lot of cases, we need to work with certain machines, chemicals and hazardous processes in order to get the job done. If the hazards cannot be eliminated, the employer is required to isolate the hazards from the workers.
Eliminating and isolating hazards can be initially expensive, and can take some time to develop. But they are the preferred method of hazard management, and make good business sense in the long term.
If some hazards cannot be eliminated or isolated, the employer must minimise employee exposure. Minimisation may include extraction ventilation, job rotation and using PPE.
Personal protective clothing and equipment may seem like the cheapest way to solve a hazardous substance exposure problem, but in most cases, it ends up costing the employer more money, and may place the worker at risk.
Common respiratory protection does not provide 100% protection against the substance.
Other issues with relying upon PPE as the sole means of safety management include:
- Poorly maintained PPE (e.g. holes in gloves, unchanged mask filters) increases worker exposure
- People sometimes forget to wear the PPE
- People can find it uncomfortable to wear the PPE and may take the risk of removing it in a hazardous work environment
- Consumable PPE can cost a lot of money to replace if being used as a long-term or permanent control
- The PPE may not provide protection against a large surge of a hazardous substance in the event of an accident
- The workplace environment has to be regularly monitored to check that hazardous substances are still within safe levels.
In your workplace, the principles for dealing with hazardous substance exposure must be to:
ELIMINATE, ISOLATE, MINIMISE.
Further sources of information:
- Workplace Exposure Standards effective from 2010
- The Approved Code of Practice for the Management of Substances Hazardous to Health in a Place of Work
