It’s not news to business owners that complying with Work Health and Safety (WHS) Regulations can be a confusing exercise. Fortunately the folks at SafeWorkAustralia have put together a series of Codes of Practice to help guide Australian employers through the minefield. An approved code of practice is a practical guide to achieving the standards of health, safety and welfare required under the WHS Act and the WHS Regulations.
This particular code offers business owners practical guidance on managing the health and safety risks associated with hazardous chemicals. It encompasses substances, mixtures and articles used, handled, generated or stored at the workplace, as well as the generation of hazardous chemicals from work processes, for example toxic fumes released during welding.
The risks associated with hazardous chemicals are well known, and include both health hazards and physicochemical hazards. Health hazards can occur when chemicals are inhaled, ingested or come into contact with skin. Acute (short term) health effects can include headaches and nausea, while chronic (long term) health effects may include asthma, dermatitis or cancer. Physicochemical hazards are those that may arise through incorrect inappropriate handling or use of chemicals, resulting in hazards including explosions and fires. Knowing how to minimise these risks is certainly in the interests of everyone connected to a business, as is being equipped with the right first aid equipment in case of an incident (for example, an eyewash station).
Following the practical advice provided in this fact sheet will help you to minimise the risks posed by hazardous chemicals in your workplace.
Find out more in the following excerpt from the Model Code of Practice: Managing Risks of Hazardous Chemicals in the Workplace or download the full code in PDF format:
3. Assessing Risks
A risk assessment is not mandatory for hazardous chemicals under the WHS Regulations, though it is required for specific situations, for example when working with asbestos. However, in many circumstances it will be the best way to determine the measures that should be implemented to control risks. It will help to:
- identify which workers are at risk of exposure
- determine what sources and processes are causing that risk
- identify if and what kind of control measures should be implemented
- check the effectiveness of existing control measures.
Where the hazards and associated risks are well-known and have well established and accepted control measures, it may not be necessary to undertake a risk assessment, for example, where there are a small number of chemicals in a workplace and the hazards and risks are well understood.
Your risk assessment should also consider foreseeable failures of plant and equipment, as well as any control measures, for example:
- A power failure may impact on the operation of a mechanical ventilation system at the workplace.
- Accidental spills have the potential to corrode or impact on nearby plant or equipment.
Documenting risk assessments is not mandatory, but may help when reviewing where improvements can be made and risks controlled more effectively.
Appendix F and Appendix G provide an overview and checklist of the risk assessment process.
3.1 Decide who should do the assessment
Assessments are based on a thorough understanding of what happens, or might happen, in the workplace and should be carried out by a person or persons who have:
- a practical understanding of the WHS Regulations, codes of practice and relevant guidance materials
- an understanding of the work processes involved at the workplace
- enough resources to gather information, consult the appropriate people, review existing records and examine the workplace.
The person or persons should also have abilities to:
- interpret the information on the label and SDS of the hazardous chemical
- observe the conditions of work and to foresee potential problems
- communicate effectively and consult with workers, contract workers, managers and technical specialists
- draw all the information together in a systematic way to form valid conclusions about exposures and risks
- accurately report the findings to all parties concerned.
A single person such as a supervisor may be suitably competent to perform simple assessments. In more complex cases, several persons representing a variety of skills may need to be involved in collecting and assessing the information. This may also include workers and their health and safety representatives.
SEEKING EXTERNAL ASSISTANCE
In some cases, it may be necessary to seek external professional assistance to assist or undertake risk assessments. External assistance may be required to:
- design an air monitoring strategy
- collect and analyse samples
- interpret monitoring and testing results.
External professional assistance may also be required in the design, installation and maintenance of control measures, such as ventilation systems or fire protection systems.
3.2 Decide what sort of risk assessment is appropriate
The type of risk assessment that should be conducted will depend on the nature of the work being performed.
a) A basic assessment consists of:
- reviewing the label and the SDS of the hazardous chemicals and assessing the risks involved in their use
- deciding whether the hazardous chemicals in the workplace are already controlled with existing control measures, as recommended in the SDS or other reliable sources, or whether further control measures are needed.For example, the SDS and label report that a cleaning agent may have potential skin irritation effects and may liberate a toxic gas when in contact with certain other chemicals, while in itself it is non-volatile. The assessment indicates that workers who handle this chemical will require control measures, including the use of protective clothing and gloves and that the chemical must be kept away from incompatible materials. Without such an assessment, skin irritation or intoxication by toxic gas when handling the cleaning agent could have occurred.
b) In a generic assessment, an assessment is made of a particular workplace, area, job or task and the assessment is then applied to similar work activities that involve the use of the chemical being assessed.
For example, a business or industry association might do a generic assessment for a number of workplaces that use, handle, generate or store identical chemicals (such as service stations or dry cleaners). When conducting a generic assessment, it is important that the workplace, tasks and hazardous chemicals being assessed are identical in characteristics, properties, potential hazards and risks. Generic assessments are not appropriate for very high risk chemicals such as carcinogens.
c) A detailed assessment may be needed when there is a significant risk to health and for very high risk chemicals such as carcinogens, mutagens, reproductive toxicants or sensitisation agents in the case of health hazards. Information on the label and SDS will allow you to determine whether the chemical has these hazards. Schedule 10 of the WHS Regulations provides further information on the hazardous chemicals that are restricted or prohibited for use (see Appendix C of this Code). A more detailed assessment may also be required when there is uncertainty as to the risk of exposure or health.
In order to complete a detailed assessment, further information may be sought and decisions taken to:
- eliminate the uncertainty of any risks
- select appropriate control measures
- ensure that control measures are properly used and maintained, and
- determine if air monitoring or health monitoring are required.It may be necessary to engage external professional assistance to undertake a more detailed assessment.
STRUCTURING RISK ASSESSMENTS
Risk assessments can be simplified by evaluating the nature of the work in smaller, more manageable parts. You do not need to do a risk assessment covering each work activity in the whole workplace. Instead, evaluate the nature of the work by:
- Dividing up the workplace – If it is not practicable for the workplace to be assessed as a whole, divide it into smaller units (locations/areas or processes) to make risk assessment more manageable. Walking through the workplace and looking at floor plans or process plans will help you decide how to divide up the workplace.
- Grouping similar work– Workers performing similar work or using similar substances may be grouped together if it has been established that their exposures are representative of their group. These are referred to as similarly exposed groups. In this way, you can avoid having to repeat exposure assessments for each and every worker. If the work involves a large number of different hazardous chemicals, they may be grouped on the basis of their form, properties and the way they are used or handled. This kind of grouping may be appropriate for example, where:- a range of solvent-based paints containing a number of different solvents and additives are used in the same or similar way (for example, sprayed, brushed or applied with a roller)- solvent-based liquid pesticides are used in the same or similar way (for example, decanted, mixed or sprayed)
- Examining work practices and conditions– Once you have divided the workplace into manageable units, you should observe and consult with workers to find out how the job is actually done. Workers may sometimes not adhere strictly to standard operating procedures for certain tasks. This could be because they have devised a more efficient and/or safer method for performing that task, or because the control measures or PPE provided make it cumbersome and difficult. Workers should be encouraged to share their views and concerns on working practices and be involved in discussions on how to improve working methods. Also, it is good practice to find out what changes in workplace activities occur during cleaning, maintenance, breakdowns and during staff absences or shortages.You should take account of any information about incidents, fires, spills, illnesses or diseases that may be related to the use of the hazardous chemical. Check your accident/ incident records. Ask those doing the work if they have experienced symptoms listed on the SDS. This information will help you to determine if exposure has been significant.
CONSIDERING BOTH HEALTH AND PHYSICOCHEMICAL RISKS
Hazardous chemicals may present an immediate or long term risk to human health through their toxicological properties, or a risk to safety of persons and property as a result of their physicochemical hazards. In some cases, chemicals may present both health and physicochemical hazards, for example solvents such as benzene, toluene and xylene.
There are many common elements to assessing risks from health and physicochemical hazards, but also several key differences in the way these risks are assessed. As a consequence, the assessment of health and physicochemical risks are discussed separately in this chapter.
3.3 Things to consider in assessing health risks
The assessment of health risks from hazardous chemicals involves gaining an understanding of the situations where people can be exposed to, or come into contact with the chemicals, including the extent of exposure and how often this can occur. Health risk depends on hazard severity and level of exposure, and thus depends on both the type of chemical and also the nature of the work itself.
As with all risk assessments, the assessment involving chemical hazards needs to consider all workers potentially at risk, including those not directly involved in a work activity, as well as other people such as visitors to the workplace.
THE ROUTES OF ENTRY BY WHICH THE CHEMICAL CAN AFFECT YOUR HEALTH
The type of hazard (for example, hazard classifications of carcinogenicity, sensitisation, acute toxicity) and relevant routes of exposure (for example, inhalation, ingestion, skin contact) should be known from the hazard identification step. These are needed in the risk assessment to understand the level of risk from likely or potential exposure scenarios in your workplace.
For particulates in air, the primary health concern is effects on the lungs due to inhalation exposure. For example, crystalline silica is considered hazardous principally because of the long term, irreversible lung effects (such as silicosis), that may arise from prolonged or repeated exposure to excessive concentrations. Its hazardous properties are associated with inhalation, so the evaluation of risk should be based on the potential for breathing in the crystalline silica dust rather than other routes of exposure (for example, contact with the skin). In the case of crystalline silica, it is the respirable fraction of the dust that presents the greatest risk to workers as this fraction contains the smallest particles which can reach further into the lungs causing the most damage.
In contrast, even brief exposures to high concentrations of sodium hydroxide may lead to immediate effects which include irritation and burning of the skin, eyes and respiratory tract and blindness. Its hazardous properties relate to exposure via skin or eye contact and inhalation. Evaluation of risks to health for sodium hydroxide (caustic soda) should therefore consider the potential exposure through all of these routes.
Some chemicals may exhibit ototoxic effects. That is, they may cause hearing loss or exacerbate the effects of noise. Evaluating the use of these chemicals should be carried out in conjunction with the Code of Practice: Managing Noise and Preventing Hearing Loss at Work.
THE PHYSICAL FORM AND CONCENTRATION
Some substances may be virtually harmless in some forms (such as a block of metal, a piece of wood or granulated solid chemicals) but may be very hazardous in another form (such as fine dust particles or fume that can be readily inhaled or solutions that may be splashed and readily absorbed through skin). This is also an important consideration in assessing risks from physicochemical hazards.
The concentration of hazardous ingredients is also an important factor in the overall risk. Concentrates or pure substances may be extremely hazardous, while dilute solutions of the same chemical may not be hazardous at all.
THE CHEMICAL AND PHYSICAL PROPERTIES OF THE SUBSTANCE
Gases or liquids with low boiling points or high vapour pressures can give rise to high airborne concentrations in most circumstances, whereas high boiling point liquids such as oils are only likely to create a hazardous airborne concentration if they are heated or sprayed. Chemicals with a very low or high pH (for instance, acids and caustics respectively) are corrosive to the skin and eyes.
Some substances give off distinctive odours which can alert workers to the presence of a hazardous chemical. For example, hydrogen cyanide has a smell of bitter almonds. However, not everyone can smell hydrogen cyanide and higher concentrations of hydrogen cyanide can also overload nasal receptors resulting in workers being unable to detect it. Hazardous chemicals can also have no odour. Thus, odour should not be relied on as a means of detecting the presence of hazardous chemical.
The chemical and physical properties are also important in assessing risks from physicochemical hazards, described later in this chapter.
DETERMINING WHO COULD BE EXPOSED, AND WHEN THIS COULD OCCUR
Workers can come in contact with a hazardous chemical and any waste, intermediate or product generated from the use of the substance if they:
- work with it directly
- are in the vicinity of where it is used or likely to be generated
- enter an enclosed space where it might be present
- disturb deposits of the substance on surfaces (for example, during cleaning) and make them airborne
- come into contact with contaminated surfaces.
You should consider all people at the workplace, including those who may not be directly involved in using, handling, storing or generating a hazardous chemical, such as:
- ancillary or support/services workers (be aware that cleaners, maintenance and laboratory staff are often exposed to both the hazardous chemicals they use in the course of their work, such as cleaning products, and the hazardous chemicals used in the workplace by other workers)
- supervisors and managers.
You should consider:
- how specific tasks or processes are actually carried out in the workplace (for example, decanting, spraying, heating). By observing and consulting workers you can find out if they are not adhering strictly to standard procedures or if procedures are not adequately providing protection to workers.
- the quantity of the chemicals being used. Use of larger quantities could result in greater potential for exposure
- the risk controls in place and their effectiveness. For example, a ventilation system may be in use but when poorly designed, installed or maintained it may not achieve the correct level of protection (such as if filters are not regularly cleaned),
- whether each worker’s work technique has a significant bearing on their level of exposure – poor techniques can lead to greater exposure
- workers who may be working alone with hazardous chemicals and if any additional precautions or checks may be necessary in case they become incapacitated.
HOW OFTEN IS EXPOSURE LIKELY TO OCCUR AND FOR HOW LONG?
The total dose (amount) of a hazardous chemical a worker is likely to receive increases with an increase in the duration or frequency of exposure. Estimations of the duration and frequency of exposure can be based on observation, knowledge and experience of the work. Seek information from your workers and their health and safety representatives to find out:
- Which work activities involve routine and frequent exposure to hazardous chemicals (for example, daily exposure, including during end of shift cleaning) and who are the people performing these activities?
- What happens when non-routine work, production of one-off items or isolated batches, trials, maintenance or repair operations are performed?
- What happens when there are changes to work practices in events such as cleaning, breakdowns, changes in volume of production, adverse weather conditions?
- Are there differences between workers within a group? Anyone whose work habits or personal hygiene (for example, washing before eating, drinking or smoking) are significantly different should be considered separately.
WHAT IS THE ESTIMATED EXPOSURE TO HAZARDOUS CHEMICAL?
Once you have investigated the hazardous chemicals, the quantities used, the frequency and duration of exposure, the effectiveness of the controls already in place, and whether workers are working directly with the substance this information should then be used to estimate the level of exposure.
Inhalation exposure can be determined by personal sampling. Information on the level of airborne concentrations of chemicals can also be obtained from static area sampling, however this method is not acceptable for determining compliance with exposure standards.
Air monitoring should be carried out by a person such as an occupational hygienist with skills to carry out the monitoring according to the appropriate standard and to interpret the results. Results from air monitoring indicate how effective your workplace controls are, for example whether ventilation systems are operating as intended. Records of air monitoring for airborne contaminants with exposure standards must be kept for a minimum of 30 years, and must be available to workers who are exposed.
An estimation of the amount of exposure to hazardous chemicals can sometimes be obtained by observation. For example, you might look for evidence of fine deposits on people and surfaces, or the presence of dusts, mists or fumes visible in the air (for example, in light beams) or the presence of odours.
An indication of the airborne concentrations of hazardous chemicals can often be obtained by simple tests, such as indicator tubes or dust lamps. However, in most cases the amount of exposure may vary throughout the day, so such tests may not establish workers’ exposure with confidence and it will be necessary to undertake detailed air monitoring. For chemicals that present a very high hazard, such as carcinogens, mutagens and reproductive toxicants, you should consider undertaking air monitoring to determine the level of exposure.
COMPLYING WITH EXPOSURE STANDARDS
As described in Section 1.5 of this Code, you must ensure that no person at the workplace is exposed to a substance or mixture in an airborne concentration that exceeds the exposure standard for the substance or mixture. Air monitoring may be necessary to ensure that workers are not exposed to airborne concentrations above the chemical’s exposure standard.
Some chemicals with exposure standards can also be absorbed through the skin – these are given a notation of ‘Sk’ in the publication Workplace Exposure Standards for Airborne Contaminants.
Biological monitoring may be a helpful means of assessing a workers’ overall exposure to a hazardous chemical that can be absorbed through the skin as well as inhaled.
Where results of monitoring show concentrations of airborne contaminants approaching or exceeding the exposure standard, you should review your control measures. Even if monitoring indicates that exposure is below an exposure standard, sensitive workers may still be at risk. Exposure standards do not represent a ‘no-effect’ level which makes exposure at that level safe for all workers, therefore you should ensure that exposure to any hazardous chemical is kept as low reasonably practicable. This includes exposure to hazardous chemicals that do not have exposure standards.
Some chemicals, such as isocyanates, are known to be sensitisers and can induce an adverse reaction in workers at levels well below the exposure standard once sensitisation has occurred. If a worker becomes sensitised to a chemical, the exposure standard for that chemical is no longer relevant and control measures such as improving engineering controls or job rotation to remove the affected worker from potential exposure to the chemical should be implemented.
For more information on how to interpret exposure standards and comply with the WHS Regulations, refer to Safe Work Australia’s Workplace Exposure Standards for Airborne Contaminants and Guidance on the Interpretation of Workplace Exposure Standards for Airborne Contaminants.
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Image Courtesy: Bo Gordy-Stith