Safety data sheets are of immense importance in informing workplace risk assessments.

This post explains how the safety data sheet (SDS) is used in COSHH assessment for health and the environment risk. It is also a plea to SDS authors to add useful, specific and quantitative recommendations in their SDSs to improve their utility for risk assessment purposes.

Part 1 of this series on chemical risk assessment describing the Chemical Safety Assessment can be found here.

If you wish to find out more about our services for risk assessment or specifically COSHH assessment, see our services page or contact us. For help with the jargon, check our glossary.

Risk assessment

The UK Control of Substances Hazardous to Health (COSHH) Regulations [1] implement the EU Chemical Agents Directive 98/24/EC [2].

The legislation requires that employers conduct a risk assessment in the workplace. It concerns all types of workplace substances, such as welding fumes, wood dust, microbes, and ‘wet work’, but we will focus on chemical products.

All chemical substances may be used safely, even if they are highly hazardous, provided that exposure of workers can be maintained below acceptable limits. This principle thus differentiates between risk, and hazard, as follows:

Risk = Hazard × Exposure (Equation 1)

This equation gives a useful qualitative appreciation of how risk can be managed through an understanding of hazards (eg organ toxicity, skin irritation, or carcinogenicity) of a product, and how workers come into contact with it (exposure assessment).

This post explains how the SDS is used in COSHH assessment for health and the environment risk. Risk assessment for fire and explosion is a separate topic.

COSHH assessment

COSHH legislation obligates employers to assess the risk to their employees from their work activities. The employer then installs measures to protect their worker’s health.

Management has to determine:

• the hazards posed by a particular chemical product
• the potential exposures of workers from the tasks they undertake
• what measures to put in place to control the exposure to safe levels.

The legal requirement is for assessment to be ‘suitable and sufficient’. The COSHH assessment should be proportionate to the risk. It can be straightforward to assess everyday chemical products in a non-chemical environments, for example using hazardous cleaning products in an office. In this case a pragmatic, common sense approach is OK:

• identify the hazardous products used in the workplace
• for each product, determine the hazards, as given in your supplier SDS (see Table 1), and the routes of exposure (eg inhalation, skin contact, eye contact, ingestion).
• hazard identification may also include the environment
• think about the tasks that workers undertake using the product, and identify possible contact (eg splashing in the eye, inhalation of spray)
• check the product SDS (particularly Section 8: Exposure controls/personal protection), and think about measures and working practices that minimise risk, eg wearing gloves for harsh cleaning products, or a particulate mask for regular use of sprayed products, or instruction not to put products down the drain
• document the assessment
• put measures in place to prevent harm, eg training staff, providing gloves, installing signage, or providing a container for disposal of waste solvents.

Table 1 below shows the Sections of the SDS and how it supports the COSHH assessment. A fuller guide to SDS content is given here.

Section 2: hazards identification	hazard classification according to the CLP Regulation (1272/2008), identifying most of the common hazards from chemical products, and also summarising hazards not covered by classification, such as endocrine disruption, bioaccumulation potential, or skin absorption
Section 3: composition/information on ingredients	identifies the ingredients that are responsible for the product being hazardous, and their concentration in the product
Section 4: first aid measures	treating workers who have been exposed, and what equipment should be on hand to prevent further harm.
Section 5: firefighting measures	tackling fires and identifies consequent chemical hazards
Section 6: accidental release measures	how to clean up spillages of the product and what equipment should be on hand
Section 7: handling and storage	precautions for safe use and storage of the product
Section 8: exposure controls/personal protection	safe levels of exposure for workers, monitoring requirements, and recommended risk management measures that should be implemented in the workplace
Section 9: physical and chemical properties	helps the employer understand the nature of the product and therefore the likely exposures, eg volatile solvent likely to be inhaled
Section 9: physical and chemical properties, and Section 10: stability and reactivity	hazardous physico-chemical properties such as fire and explosion, and compatibility with other chemicals
Section 11: toxicological information	detail on the health effects from the product. Section 11.1 gives toxicological information on hazards covered by the CLP classification system (ie most of the common hazards), and Section 11.2 any other hazards. This Section identify the hazards (organ toxicity, eye irritation, allergy), and also routes of exposure (eg inhalation, skin contact), doses that result in harm, and whether the effects are short- or long-term.
Section 12: ecological information	data on environmental toxicity, dispersion, and degradation
Section 13: disposal considerations	safe disposal of the product

For five or more employees, management must record the assessment but we recommend in any case writing down what steps you have taken to identify the risks and a list of the actions you are taking to control the risks to health. The larger the workforce the greater the need for formal assessment and documentation.

For use of highly hazardous products, while the process is the same, the COSHH assessment is more rigorous. It is likely to involve a technical, quantitative approach to make sure that worker exposures are within calculated safe limits.

For some hazardous properties, particularly carcinogenicity, mutagenicity, and respiratory sensitisation, it is not always possible to derive safe levels. For substances with these properties, worker exposure should be reduced to as low as reasonably practicable (ALARP). This usually mean containing them in a closed system, in effect reducing everyday exposures to zero.

Larger chemical companies will have health and safety procedures and systems in place for handling of hazardous chemicals. Often, there will be a stock list and a procedure for when a new hazardous chemical is ordered.

For this more rigorous approach the steps described below should be followed.

Hazard identification

The first step for COSHH assessment for a new product used in the workplace is to understand the hazards it presents.

The employer can source information for the COSHH assessment from the product safety data sheet (SDS). The employer should receive an SDS from their supplier for any product that is: (a) classified as hazardous according to the CLP Regulation (1272/2008); or (b) contains a substance with an EU exposure limit value. You can also request an SDS if the product contains hazardous ingredients above a certain threshold (usually 1%, but other thresholds may apply).

Hazard information useful for COSHH assessment is presented in the SDS in Table 1. Sections 2, 3, 9, 11 and 12 give a thorough evaluation of the hazards of the product.

Most chemical products are mixtures formulated for a specific purpose. Where possible, the mixture SDS should give information on the mixture. Where this is not available, ie not measured and not feasible to calculate, then ingredient information is often given and can be useful.

Substance classification and hazard information can be checked against the REACH Registration dossier available at the European Chemicals Agency’s (ECHA’s) website [3].

Some hazards are easy to understand. Local effects, such as skin and eye irritation cause pain, redness, and swelling at the site of contact. If contact is foreseen in use, these hazards are often managed with personal protective equipment (PPE) such as gloves and eye protection.

Other hazards, such as allergy, long-term toxicity, and carcinogenicity, require careful consideration of routes of exposure, dose–response effects, and exposures of different populations (eg workers and consumers).

Employers should keep records of health issues in the workforce that may be due to exposures to chemicals. Monitoring trade journals may also identify potential effects.

Exposure assessment

The exposure assessment for COSHH consists of the following stages:

• identification of workers who are exposed to the product, including vulnerable workers such youngsters or pregnant women
• identification of the tasks undertaken by each worker, including the effects of the work on the exposure, such as higher breathing rates for manual labour
• identification of potential routes of exposure
• Measurement or estimation of exposure if warranted.

Worker exposure is effectively measured by monitoring. Monitoring is used to confirm that risk management measures are adequate. There are several methods for monitoring, but commonly involve:

• measuring air concentrations of a particular substance in the workplace to give an estimate of inhalation exposure.
• measuring concentrations of substances or their metabolites in biological samples (eg respired air or urine) taken from potentially exposed workers
• Measuring skin exposure by swabbing exposed areas.

Advice on monitoring procedures is given in the SDS Section 8.1 (control parameters).

Sometimes workplace exposures can be estimated using ‘modelling’, ie using specialised software (eg Chesar and ECETOC TRA). In many cases these tools have been used for the chemical safety assessment (CSA, see Part 1) for substances and documented in ingredient SDSs, particularly if it is an extended-SDS (ext-SDS) with an Annex containing exposure scenarios. In such cases, the risk management measures given in the SDS will adequately ensure exposures are within acceptable limits.

Safe or acceptable exposures

Section 8.1 (control parameters) should also give specific advice for safe (‘no-effect’) levels.

Some substances (around 500 in the UK) have occupational exposure limits (OELs; as published in the UK HSEs EH40). These are maximum airborne concentrations of particular substances either for a working day (8 h), or for short, 15 min periods.

Some of these OELs are copied from EU legislation (Chemical Agents Directive 98/24/EC). Products that contain ingredients with an EU OEL (known as an IOELV) have requirements for listing those ingredients, and provision of the SDS.

OELs generally only apply to airborne concentrations, although some limits for chemicals in biological samples (respired air, urine) from workers are available.

REACH legislation has provision for calculating safe limits for other routes, including dermal exposure, and disseminating the information down the supply chain. These are the Derived-No-Effect Levels (DNELs, applicable to human health) and Predicted-No-Effect Concentrations (PNECs, applicable to the environment) also listed in Section 8 of the SDS. REACH legislation requires downstream users to abide by these control parameters, or provide scientific justification for not doing so.

Other countries may produce lists of workplace exposure limits, eg the US ACGIH or the German MAK. These do not have legal status within the UK, but may be useful benchmarks for the employer.

Exposure through all routes must be considered. Inhalation is often the main route giving systemic toxicity, but the assessor has to combine other significant exposure such via the route for substances able to pass through the skin – this property is indicated for substances in the lists of OELs.

Risk management measures

The employer has a several options for controlling worker exposure within safe limits. Although personal protective equipment (PPE) is seen as a simple measure, it has the lowest priority in the hierarchy of controls:

• eliminate the product and use a safer alternative
• use a safer form of the product, eg pellets rather than powder
• change the process to emit less of the product, eg loading reactors by pipe rather than manual addition
• extract emissions of the substance near the source
• reduce the number of workers involved in the process, and the time that they may be exposed
• provide PPE such as gloves, coveralls and a respirator.

The SDS in Section 8 (exposure controls/personal protection) should give specific advice for risk management when using the product, particularly:

• ventilation, including type, efficiency, and air changes per hour where appropriate
• personal protective equipment, eg type of glove material, thickness, and minimum penetration time
• environmental controls.

The employer should assess the products and workplace and implement suitable and sufficient measures to control worker exposures. If necessary, the effectiveness of the measures can be verified through monitoring.

Documentation

Identified risk management measures need to be documented and passed on to supervisors and workers. Some examples and formats for the COSHH assessment are given on the UK HSE website [4].

Chemical processing is typically a complicated process, and there are other potential areas that should be addressed in the COSHH assessment:

• installation, checks and maintenance of equipment
• training of workers in handling hazardous materials and the use of equipment, including PPE
• organisation chart and responsibilities for duties related to risk management.

These parts of the COSHH assessment are not covered in the supplier SDS.

COSHH vs REACH ext SDS

The REACH chemical safety assessment is complimentary to the COSHH risk assessment. Users of the chemical product are obliged to follow both sets of legislation.

For hazardous substances supplied at >10 tonnes per year in the EU, a comprehensive risk assessment is required as part of the REACH Registration dossier, ie the Chemical Safety Assessment (CSA) (see Part 1).

The CSA also contains exposure scenarios (ESs) for each activity (eg pouring, mixing, spraying) in the life cycle of the product. The ESs give recommended risk management measures (RMMs) that adequately control exposure to safe levels if implemented in the workplace.

ESs should be appended to the SDS as an Annex giving the extended safety data sheet (ext-SDS). The ext-SDS is distributed down the supply chain to downstream users (DUs) who should check their use is covered by the ESs, and implement the risk management measures described therein.

If the use is not covered, the DU can ask their supplier to modify the ext-SDS, or conduct their own CSA to determine ESs for their use.

The REACH CSA is complimentary to the COSHH risk assessment; the former document gives supplier recommendations for control parameters and risk management measures, while the latter gives steps for practical implementation of these recommendations. Put another way, the SDS gives advice on the safe handling of the product, but the COSHH assessment adapts this to the specific workplace and workforce.

Users of the chemical product are obliged to follow both sets of legislation.

While the theory of this two-pronged approach to chemical risk assessment is good, there have been practical issues with the quality of SDSs, and the ESs in particular. This hampers the SDS being as useful as it should be in COSHH assessments.

Many SDSs are generated by software, and populated with bland, generic statements. The author of the SDS should check and expand on the information in the SDS to ensure:

• the data Sections of the SDS are as complete as possible
• quantitative specification of risk management measures are made where possible
• the SDS is tailored to the product, its use, and the quantities likely to be used.

Too often, suppliers see SDS provision as a legal compliance issue, rather than as a communication tool and an important part of product stewardship. This blog emphasizes that SDSs are of immense importance in informing workplace risk assessments. Authors have a responsibility to ensure SDSs contain useful and practical information to downstream users of their products. The DUs need accurate information to perform the COSHH assessment and ensure safe use of the product.

References

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[1] Control of Substances Hazardous to Health Regulations 2002 (COSHH) (SI 2002/2677), as amended (also implementing 90/394/EEC on carcinogens at work).

[2] Council Directive 98/24/EC of 7 April 1998 on the protection of the health and safety of workers from the risks related to chemical agents at work (as amended).

[3] Information on Registered Substances; Chemical Substance Search; European Chemicals Agency (ECHA), available at the ECHA website: http://echa.europa.eu.

[4] Example COSHH risk assessments; UK Health and Safety Executive: https://www.hse.gov.uk/coshh/riskassess/index.htm.