7. Manage and control risks from hazardous chemical agents (HCA)

When hazardous agents are used in the workplace the following issues should be considered:   

• How hazardous agents should be used.  

• How persons are exposed to hazardous agents. 

• Whether the risk from the hazardous agent is significant; and  

• How exposure to hazardous agents in the workplace should be controlled.

The 10-step process outlined further on in this course could be followed to: 

• Identify hazardous agents used in the workplace.  

• Assess the risk from their use.  

• Determine and implement appropriate control measures so that they can be handled and used safely; and 

• Review and monitor the effectiveness of control measures used.

Management of risks from hazardous agents should be applied wherever the work is being carried out, for example the different locations where cleaners are carrying out cleaning work while using hazardous agents.

Before we discuss this process, let us first look at the explanation of an assessment and the types of assessments that could be conducted with regard to hazardous chemical agents.

An assessment is the examination of ways in which a hazardous agent is used in the workplace and the health risks involved.  

The purpose of the assessment is to enable decisions to be made about: 

• Appropriate control measures,  

• Training,  

• Monitoring, and 

• Health surveillance.

These decisions will depend on the risk that arises from the use of a hazardous agent under particular working conditions.

The way in which an assessment is conducted depends on the circumstances of the workplace.  Two possible methods are:  

 1. Workplace specific assessments.

An example of a workplace specific assessment could be a walk-through survey of the workplace using a checklist.  

The checklist should be based on information on labels and SDSs, for example, risk phrases on labels could be used to get an idea of how a person using an agent may be exposed.

In some cases, considerably more detail will be required, particularly where:  

• A significant risk to health is suspected; or  

• There is uncertainty about the degree of risk; or  

• There are complex chemical processes and/or exposures involved.  

In these cases, additional detail on all facets of the assessment may be required.  This could include the use of outside professional assistance.

 2. Generic assessments.

An example of a generic assessment may be in the use of hazardous agents at service stations.  In this case, the nature of the hazard and the degree of risk at one service station may be comparable to the degree of risk at others.  

Therefore, a single assessment of the activity can be applied to other workplaces where the use for the hazardous agent is the same. 

When a generic assessment is undertaken it should be checked for validity at each individual workplace.

Below is a schematic overview of the process for the assessment of health risk arising from the use of hazardous agents in the workplace.

The purpose of a risk assessment is to allow appropriate control measures to be developed.  Once hazards have been identified, they should be assessed in terms of their potential to do harm.  

All the factors in risk assessment are interconnected.  For the purposes of performing an assessment, you should consider the factors in isolation and then consider their combined effect.  The factors are the:  

• Risk associated with the hazard (for example, agents are inhaled, get on skin or in eyes).  

• Probability that an event or an exposure will occur.  

• Length of time of exposure a person has to the hazard (ranging from occasional to continuous contact with the hazard); and  

• Possible consequences that may result, for example, causing liver disease, cancer, and burns.

The following seven steps can be implemented to manage the risks from hazardous chemical agents:

In a small business, assessments are usually undertaken by an employer or manager, in cooperation with the workers.  The tasks needed to carry out an assessment may be delegated by the employer to other persons at the workplace.  However, the overriding responsibility for the accuracy and appropriateness of the assessment is held by the employer.  

Professional persons from outside the workplace may aid with elements of the assessment which require special expertise.  If your workplace is large, it might be useful to establish a team, for example, the relevant manager/supervisor, workplace health and safety representative to assess particular work.  

The assessor should have sufficient knowledge and skills to evaluate the health risks to workers arising from the use of a hazardous agent.  He/she should understand the relevant regulatory provisions and codes of practice and have a sound knowledge of the work activity.  

If an outside consultant is engaged to assist with the assessment, ensure that workers who have a thorough knowledge of the work, are involved.  

The assessor should have the authority to do the work necessary for the assessment, and enough resources to gather information, consult the appropriate workers, review existing records, and examine the workplace.

He/she should also be able to:  

• Interpret the information on an SDS and labels.  

• Observe the conditions of work and foresee potential problems.  

• Communicate effectively with everyone at the workplace.  

• Draw all the information together in a systematic way to form valid conclusions about exposures and risks; and  

• Report the findings accurately to all parties concerned.

If there are any limitations in the experience and knowledge of the assessor/s, it may be necessary to supplement this knowledge by arranging appropriate training in risk assessment or engaging specialist assistance.  

If a team approach is used, members of the assessment team might be assigned different tasks.  Individual findings should be communicated to the person selected to coordinate the assessment.  This person should reach appropriate conclusions about risks and determine control measures.  In larger workplaces where many assessments are needed, an overview committee may be established to coordinate the assessments.

To make the risk assessment easier, the work that utilises a hazardous agent should be divided into:   

• Jobs,
• Tasks, or  
• Processes.

Visiting the workplace and looking at floor plans or process plans should help with this.  Dividing a small workplace in this way may not be necessary when only a few agents and persons are involved.

The next step is to identify whether or not there are hazardous agents used in the workplace.  When identifying a hazardous agent used or intended to be used, in the workplace, it is important to recognise that it could exist in various states or forms, i.e. solid, liquid, gas, vapour, dust, mist or fume.   

Agents used in the workplace should be identified by:  

• Referring to stock lists, inventories, and registers.  

• Checking all locations where agents are used or stored; and  

• Considering all agents that are used in, or that arise from, ancillary work such as maintenance and repair, cleaning, research, or testing.

From the information collected in Step 3 refer to the SDS and labels for information on whether the agent is hazardous.  

All hazardous agents that have been identified must be included in the hazardous agents register along with a copy of the SDS.

If you are unsure if the agent is a hazardous agent, contact the supplier.

The following Information should be obtained about the hazardous agents in the workplace:  

• Routes of exposure, and  

• Recommended control measures and other action to prevent or minimise risks.  

For most risk assessments, container labels and SDS’s will provide this information.  Where the nature of the hazard is very serious, or chemical processes are complex, it may be necessary to obtain more detailed information from other sources, for example, from the manufacturer or supplier of the agent, a designated doctor, or an occupational hygienist.

A “walk-through” inspection should provide information about hazardous agents used in each work area.  In assessing existing processes, it is important to talk to workers in each area regarding practical information about work practices and procedures.

Workers could describe what happens during a breakdown, maintenance, changes in personnel or volume of production, weather conditions or other changes that can affect the ways hazardous agents are handled and used.

If a job, process, or other work unit is being planned, an evaluation of the relevant work process, plan or design should be undertaken before the commencement of the operation.  This will enable any hazards inherent in each step of the process and consequent risks to be identified.  Suitable control measures can then be determined.

A metal shop proposes to introduce electroplating, which will result in new chemicals being used in the workplace.  Therefore, it will be necessary to implement different measures to control the exposure of workers on the electroplating line.

The following questions should be answered when inspecting and evaluating exposure:

1. Is the hazardous agent released or emitted into the work area?

In determining whether a hazardous agent is released or emitted into a work area, consider the following:

• • Evidence of contamination: Dust or fumes visible in the air or on surfaces, substance visible on a person’s skin or clothing, odour of substance, visible leaks, spills, or residues. Note: the use of odour should be used with caution as it is not necessarily an indicator of the levels permitted by Regulation.
  • Handling agents, for example, powders not in containers.
  • Chemical splashes; and
  • Workers’ experience or symptoms of exposure. 

If the hazardous agent is not released or emitted into the work area, go on to Step 7.

2. Are workers exposed to the hazardous agent through inhalation, ingestion, skin, or eye contact, or is there a possibility of accidental injection into the body? 

It is important to identify the types of exposure which might affect workers.  Workers involved in production, repairs, maintenance, cleaning, or office work may all face different types of exposure.  Also consider contractors on site and people who might be exposed in an emergency such as a chemical spill, leak, or fire.  

People may be exposed by:

• Working directly with the hazardous agent.
• Working near or passing through areas in which the hazardous agent is stored, transported, disposed of, or produced by discharge of emissions, e.g. exhaust.
• Entering a confined space in which the hazardous agent might be present; or
• Cleaning, performing maintenance or other work in areas where the hazardous agent might be present.  

3.  How much are workers and other persons exposed to hazardous agents and for how long?

It is important to identify the number of hazardous agents to which workers are exposed and the length of time over which exposure occurs.  In particular, remember that exposure standards for hazardous agents are calculated on a daily 8-hour exposure.  Where workers have been exposed in excess of 8 hours during their working day specialist help may be needed to apply the exposure standard.  In identifying how much and for how long, ask:

• What degree of exposure is expected?
• Does exposure occur intermittently or continuously?
• Does exposure occur frequently?
• What are the different routes of exposure?
• How many workers are exposed? 

If monitoring is required it should be carried out by a person who has sufficient knowledge, skills and experience in the techniques and procedures listed below:

• When and how the monitoring is to be done.
• The sampling procedures and analytical methods to be used.
• The sites and frequency of sampling; and
• How the results are to be interpreted. 

Below is an example of information that should be contained in monitoring records:

• The hazardous agent concerned, the results of monitoring and when it was done.
• What monitoring procedures were adopted, including the duration of sampling.
• The locations where samples were taken, the operations in progress at the time and, in the case of personal samples, the names of those individuals concerned.
• Whether the results reflected normal operating conditions.
• Who undertook the analysis of the results.
• How the results were interpreted; and
• The effectiveness of control measures.

4. What control measures are used or proposed? Are the existing control measures effective, properly used and maintained?  

During a walk-through inspection, consider the following points:

• Are any engineering controls in place, such as, isolation or enclosure of processes?
• Are effective general ventilation and local exhaust ventilation systems in place effective and adequately maintained?
• Are workers trained in the proper use and maintenance of control measures?
• Do work practices ensure safe handling?
• Are appropriate personal protective clothing and equipment used and maintained in a clean and effective condition?
• Are facilities for changing, washing, and eating meals maintained in good condition?
• Good personal hygiene practices can help reduce worker exposure to a hazardous substance.
• Are good housekeeping practices in place?
• Are all hazardous agents stored correctly?
• Is disposal of waste appropriate?
• Are appropriate emergency procedures and equipment in place (for example, eye wash, safety shower, etc.)?  

5. Are there any risks associated with the storage and handling of the hazardous agent?

The risk associated with the storage and handling of a hazardous agent in the workplace often relates to spillage and fire.  Under these circumstances, workers might be exposed briefly but at high concentrations, i.e. the exposure is acute.  As a result, the hazardous agent may also be classified as dangerous goods.  These risks are different from those associated with day-to-day exposure and should be considered separately.

Stated dangerous goods should not be confused with hazardous agents – they are classified according to different criteria. Dangerous goods are classified on the basis of immediate physical or chemical effects, such as fire explosion, corrosion and poisoning, the effect on property, the environment, or people, while hazardous agents are classified only in the basis of health effects (whether they be immediate or long term).

The conclusions at Step 6 will provide the necessary information to establish:  

• The nature and severity of the hazard for each hazardous agent.  

• The degree of exposure of persons in the workplace; and 

• Whether existing control measures adequately control exposure.

Conclusions from the risk assessment:  

It should now be possible to establish which of the following conclusions apply to the assessment and what action is required.

This conclusion applies where it is unlikely that the use of the hazardous agent will adversely affect the health of persons at the workplace and the risk is not likely to increase in the future.  

For example:

• The amounts or rate of use of a hazardous agent are too small to constitute a risk, even if controls fail.
• The operation obviously and strictly conforms to the information contained in the SDS and label.
• Similar assessments in the past have confirmed the risks were not significant, and work conditions now are the same.

Significant risk means that the work with a hazardous agent is likely to adversely affect the health of workers and other persons at the workplace. For example, there would be a “significant risk” if:

• The severity of the acute⁸ or chronic⁹ health effects from exposure to the hazardous agent are substantial; or
• There are no control measures in place at the workplace or the controls that are in place are not adequate to protect workers from exposure to a hazardous agent; or
• The level of exposure is high.

Consultation should take place to decide if the risk is significant. If the contaminant concentration in a person’s breathing zone is above half the national exposure standard, a plan should be developed to review the levels before the next assessment. Further action in reviewing the exposure will assist in ensuring that the concentration does not reach a level which poses a significant risk to health and safety.

This conclusion usually applies to conditions where serious health effects could result if the control measures fail or deteriorate. This usually results from the use of a highly toxic hazardous agent or where the potential exposure is high.  

Risks, while presently adequately controlled, could increase in the future, owing to, for example:

• Undetected deterioration in the efficiency of control measures.
• Plant including PPE or system failure.
• Control measures not used properly.
• Human error from lack of awareness.
• Ineffective monitoring.
• Insufficient or lack of ongoing training.
• Changes in methods or rate of work; and
• A significant increase in the quantity of hazardous agents used.

Action required:

• Determine precautions to maintain controls and minimise chances of higher exposure occurring.
• Determine additional measures for regaining control if a high-risk event occurs, despite precautions, and
• Determine if monitoring or health surveillance is required to check on effectiveness of controls.

The following indicates where the use of a hazardous agent is likely to constitute a risk and further investigation may be necessary if:

• Dusts, mists, or fumes are visible in the air, for example in light beams, and there are persistent or widespread complaints of illness, discomfort, irritation, or excessive odour.
• Hazardous agents are splashed.
• Control measures are broken, defective or badly maintained, for example a poorly maintained extraction system which no longer draws a hazardous agent away from the work area.
• Recognised safe work practices are not being observed.
• Airborne concentrations approach or exceed exposure standards.
• Ill-health associated with exposure has been detected by health surveillance; and
• Results of biological monitoring indicate workers are at risk.

Action required:

• Identify and implement immediate measures for preventing or controlling exposure.
• Work out if there is a need to stop the process.
• Begin review of longer-term control requirements.
• Re-evaluate exposures when the upgraded control measures are in place; and
• Determine if monitoring or health surveillance is required.

If the level of exposure cannot be estimated with confidence, further investigation is necessary. Atmospheric monitoring might be required to estimate the level of exposure. For a hazardous agent absorbed through the skin, ingested, or inhaled, biological monitoring might be required. A detailed evaluation might be needed if there is the potential for a major hazard such as a large leak or spill. In these cases, relevant specialist advice would probably be required.  

If there is not enough information to estimate the risks, additional information should be obtained from other sources, such as suppliers, occupational health and safety consultants and industry or trade associations. 

Action required:

• Obtain additional information or conduct a more detailed assessment.
• Obtain specialist advice if necessary; and
• Implement good work practices to minimise exposure.

The following three steps can be implemented to control the risks from hazardous agents.

Control or prevention of exposure is undertaken by implementing appropriate control measures. When considering methods to control exposure, all the possible routes of entry to the body should be taken into account.  

Control measures are not mutually exclusive and in some circumstances two or more control measures may be required to reduce exposure to as low a level as is practicable.  

Control measures for a hazardous agent should be considered in the planning of any new workplace or modifications to an existing workplace. The costs of the control should be considered in the same way and at the same time as all other plant and process costs.

Hierarchy of control measures:

The hierarchy of control measures is a list of control measures, in priority order, that can be used to eliminate/minimise exposure to a hazardous agent. The order in which control measures should be implemented is:

• Elimination.
• Substitution.
• Isolation.
• Engineering Controls.
• Administrative Controls.
• Personal Protective Equipment (PPE).

Application of the hierarchy of control measures involves firstly assessing whether a hazardous agent can be eliminated. Where this is not practicable, substitution should be considered. However, if this is not practicable, consideration should be given to each of the other control measures (isolation, engineering controls, safe work practices and use of personal protection equipment) in turn, with the objective of identifying a control measure or combination of control measures that will eliminate or minimise exposure. 

Control Measures:

Elimination: Where a work activity involves the use of a hazardous agent that is not essential to the work activity the hazardous agent should be eliminated, wherever practicable.

Elimination includes:

• – Using a physical process rather than a chemical process to clean an object, for example, use of ultra-sound.
• – Using clips, clamps, or bolts instead of adhesive; and
• – Purchasing supplies of a material in a ready-cut and sized form rather than carrying out a dust producing cutting process on site.

Substitution: Includes substituting a less hazardous agent, the same agent in a less hazardous form or the same agent in a less hazardous process.

Substitution includes:

• – Replacing a chlorinated degreasing solvent with a detergent.
• – Using a water-based paint in place of an organic solvent-based paint.
• – Using a hazardous agent in paste or pellet form rather than a dusty powder; and
• – Brush application of paint rather than aerosol application.

Isolation: Involves separation of the process from people by distance or the use of barriers to prevent exposure.

A booth in an underground car park is supplied with fresh air to minimise carbon monoxide exposure for a parking attendant.

Engineering Controls: By the use of plant or processes which minimise the generation of a hazardous agent, suppress or contain a hazardous agent or which limit the area of contamination in the event of spills or leaks.  

Types of engineering controls include enclosure or partial enclosure, local exhaust ventilation and automation of processes.

Engineering controls are:

• – Ventilated booths for spraying paint or fibre glassing.
• – Robot welding.
• – Local extraction systems attached to grinding machines.
• – Automation of the removal of objects from degreasing baths; and
• – Closed reaction vessels.

Administrative Controls – are work practices which require people to work in safer ways and are intended to limit the extent of exposure to a hazardous agent.

Safe work practices include:

• – Excluding nonessential persons from a work area.
• – Shift or work rotation to reduce the period of exposure for workers.
• – Regular cleaning of contamination from walls and surfaces.
• – Providing means for safe storage and disposal of hazardous agents.
• – Prohibiting eating, drinking, and smoking in contaminated areas.
• – Prohibiting the use of compressed air for personal cleaning purposes.
• – Vacuuming dust from areas where cutting processes take place.
• – Keeping lids on containers when not in use.
• – Providing and using facilities for effective decontamination; and
• – Providing first aid, safety showers and eye wash facilities, evacuation procedures and emergency procedures.

Personal Protective Equipment (PPE): The basic personal protective equipment available to guard against risks from hazardous agents includes respirators, goggles, face shields, gloves, footwear, and aprons. Self contained breathing apparatus or hazardous chemical suits may be required if the risk of exposure is significant because a hazardous agent is present in an uncontrolled environment.  

Situations where the use of suitable personal protective equipment may be necessary include:

• Where it is not technically feasible to achieve adequate control by other means. In these cases, exposure should be reduced as far as practicable by other measures and then, in addition, suitable personal protective equipment should be used to secure adequate control.
• Where personal protective equipment is necessary to safeguard health until such time as adequate control is achieved by other means, for example, where urgent action is required because of plant failure.
• During routine maintenance operations where the infrequency and small number of people involved may make other control measures not practicable; or
• Where SDS and labels indicate.

The ongoing costs (e.g. training and maintenance and/or replacement) and operator considerations (e.g. correct fit and medical factors) associated with PPE should be given significant consideration before determining it as the preferred control option.

To ensure PPE is effective as a control it should be:

• Selected for the contaminant, task, and the operator in accordance with appropriate standards.
• Readily available.
• Clean and functional.
• Checked before use.
• Correctly used when required; and
• Appropriately maintained.

Following the selection of appropriate PPE as a control measure, training should be provided to ensure it is properly used in accordance with the appropriate standards for the equipment.

The assessment report should reflect the detail of the assessment and provide sufficient information to show how the decisions about risk and controls were made.  The risk assessment record should include the following:

• Names of the assessor or assessment team.
• All personnel involved.
• A description of the hazard and routes of entry to the body.
• A description of normal operations in the work area.
• Procedures used to assess exposure.
• Procedures used to assess the degree of exposure.
• Procedures used to assess existing control measures.
• Conclusion from the assessment whether the risk was not significant or significant.
• Action to be taken.
• Induction, training, emergency procedures and health surveillance action to be taken.
• The circumstances when reassessment will be required.
• Signature, date, and position of the assessor/assessment team; and
• Signature, date, and position of the employer accepting the assessment.

Consider a standard for the format of an assessment report.

Examine all measures for the control of exposure thoroughly and test at regular intervals to ensure effective performance.  Review the controls if any work-related ill health is reported.  Establish routine maintenance including preventive service procedures, specifying:

• Which control measures require servicing.
• The servicing needed.
• The frequency of servicing.
• Who is responsible for servicing.
• How any defects will be corrected.
• Performance testing and evaluation; and
• Record of servicing.

In the maintenance department of your factory there is a Paint Shop where different types of paint are utilised to do sign writing, spray painting of equipment, etc.  The sign writer uses a lead-based paint in order to paint the base coat of all the sign boards, before painting the actual artwork.  The paints are currently being stored in the room where he does the painting.  No extraction units are installed in the Paint Shop, which is situated right in the back left corner of the Maintenance Workshop.

Give examples on how the following four engineering controls could be applied in order to improve the conditions and exposure of the sign writer:

• Use of a safer agent.
• Use a different process.
• Isolate the hazardous agent.
• Provide ventilation.

Explain how the administrative controls can listed below can be applied to reduce the exposure of the sign writer in the Paint Shop:

• Reduced work periods or job rotation.
• Limiting staff in hazardous areas.
• Limiting amounts of hazardous agents on site.
• Regular safety meetings and inspections.
• Training.
• Safe work practices and procedures.
• Labels and signs.
• Two yearly assessments and monitoring.
• Maintenance programmes.
• Good housekeeping and personal hygiene.

Personal protective equipment (PPE) is always the last resort in applying control measures.  PPE is there to protect you and must:

• Be the right type (appropriate).
• Provide sufficient protection.
• Be correctly used and stored.
• Be maintained in good working order.

If PPE causes discomfort, you should inform your supervisor.  

The sign writer in the Paint Shop has been issued with a dust mask, thick rubber gloves and an overall as personal protective equipment.  Prior to the dust mask, he used to wear a respirator with a filter, but due to the heat in the Paint Shop because of poor ventilation, he was sweating too much with the respirator and he replaced it with a dust mask.  

Discuss the appropriateness of the issued PPE and if necessary, where this could be improved.