COSHH Assessments for Workplace Health & Safety | THSP
Employers dealing with COSHH are not usually looking for theory. They are dealing with substances that are already part of their operations, and the question is how those substances are being controlled in. . .
Employers dealing with COSHH are not usually looking for theory. They are dealing with substances that are already part of their operations, and the question is how those substances are being controlled in practice. The risk does not sit in the label or the data sheet. It sits in how materials are handled, used, and interacted with during day-to-day work. Under UK health and safety law, COSHH is one of the clearest examples of how broad duties translate into specific actions. It requires employers to assess exposure, understand how harm could occur, and put controls in place that are proportionate to the risk. This is not a one-off exercise. It is part of ongoing risk management, aligned with how work is actually carried out. Where COSHH arrangements are effective, they reflect real working conditions. Assessments are specific, controls are visible, and risks are understood by those carrying out the work. Where they fail, it is usually because they are treated as generic documents rather than practical tools. Key Takeaways:COSHH assessments focus on controlling exposure to hazardous substances, not just identifying themA substance only becomes a risk when there is a realistic route of exposure, such as inhalation or skin contactEmployers must carry out suitable and sufficient COSHH assessments that reflect real working conditionsGeneric or template-based assessments often fail because they do not match how work is actually carried outEffective COSHH management requires applying the hierarchy of control, prioritising elimination, substitution, and engineering controls over PPEControl measures must be visible, practical, and consistently followed, not just documentedCOSHH applies to a wide range of substances, including dusts, fumes, vapours, and by-products of work processesAssessments must be reviewed and updated regularly, especially when processes, substances, or conditions changeCOSHH should be embedded into day-to-day supervision, training, and risk management, not treated as a one-off exerciseWhat is a COSHH Assessment and When is it Required?A COSHH assessment is the process used to identify and control risks from substances that can harm health. It sits under the Control of Substances Hazardous to Health Regulations and forms part of an employer’s wider duty to manage risk. The requirement is not limited to obvious chemicals. It applies wherever substances could cause harm through how work is carried out. The key point is that risk is created through exposure, not simply presence. A substance only becomes a COSHH risk when people can inhale it, come into contact with it, or otherwise be affected during work activities. AreaWhat COSHH RequiresWhat This Means in PracticeTypical ExamplesRelevant RegulationDefinition (COSHH)Control of Substances Hazardous to HealthIdentify substances that can cause harm through exposure during workCleaning chemicals, solvents, adhesivesCOSHH Regulations 2002Legal DutyAssess risks from hazardous substancesEmployers must evaluate exposure risk and implement controlsWorkplace cleaning, manufacturing, maintenance tasksCOSHH Reg 6Types of SubstancesIncludes chemicals, dusts, fumes, vapours, biological agentsNot limited to labelled products. Includes by-products of work processesWood dust, welding fumes, silica dust, bacteriaCOSHH Reg 2Exposure RoutesConsider how harm occursInhalation, skin contact, ingestion, injectionDust inhalation, skin contact with irritantsCOSHH Reg 6When COSHH AppliesWhere substances are used, stored, handled, or generatedApplies across all stages of work activity, not just useStorage areas, mixing processes, cutting operationsCOSHH Reg 6Risk vs PresenceFocus on exposure, not existence of substanceA substance only presents risk if workers can be exposed to itSealed vs airborne materialsCOSHH PrincipleWork ActivitiesAssess how substances are used in real tasksConsider frequency, duration, method of use, and environmentSpraying, pouring, cutting, heating materialsCOSHH Reg 6Who is AffectedIdentify those at riskEmployees, contractors, visitors, and others affected by workCleaners, operators, maintenance staffHSW Act / COSHHControl RequirementPrevent or adequately control exposureApply hierarchy of control, not just PPEExtraction systems, substitution, safe handlingCOSHH Reg 7Link to Employer DutyPart of broader risk management dutyCOSHH integrates with general risk assessments and site controlsWorkplace safety systemsHSW Act 1974A COSHH assessment is not about listing substances. It is about understanding how exposure happens and what needs to be controlled to prevent harm. When applied properly, it reflects the reality of the work being carried out, including how substances are used, who is exposed, and under what conditions. Employers should be able to show that substances have been properly assessed, that exposure routes are understood, and that controls are in place and working. This is what demonstrates compliance in practice. Not the presence of a document, but clear evidence that risks from hazardous substances are being actively managed and kept under control. What Makes a COSHH Assessment “Suitable and Sufficient”?The requirement for a COSHH assessment to be “suitable and sufficient” is central to compliance, but often misunderstood. It does not mean detailed for the sake of it, or overly complex. It means the assessment is accurate, relevant, and capable of controlling the risk in practice. A suitable and sufficient COSHH assessment reflects how substances are actually used, how exposure occurs, and what controls are needed to prevent harm. It should give a clear, workable picture of the risk, not a generic description. Where this standard is not met, the issue is rarely missing paperwork. It is that the assessment does not match reality. AreaLegal ExpectationWhat This Means in PracticeCommon Failure PointRelevant RegulationSuitable and Sufficient StandardAssessment must adequately address the level of riskFocus on significant risks, not unnecessary detail. Clear, usable controlsOverly basic or overly complex assessmentsCOSHH Reg 6Exposure IdentificationIdentify how exposure occursConsider inhalation, skin contact, ingestion, and accidental exposureExposure routes not properly assessedCOSHH Reg 6Who is AffectedIdentify persons at riskConsider employees, contractors, vulnerable persons, frequency of exposureAssumptions made without considering actual workforceCOSHH / HSW ActTask-Specific DetailReflect how work is carried outAssessment aligned to real tasks, methods, environment, and conditionsGeneric assessments copied across multiple tasksCOSHH Reg 6Control MeasuresDefine adequate controlsControls must be practical, visible, and achievable within the work activityControls listed but not applied on siteCOSHH Reg 7Use of Safety Data SheetsInform assessment, not replace itSDS used as a reference, not copied directly into assessmentsCopy-paste SDS with no interpretationCOSHH GuidanceGeneric vs Specific ApproachAssessments must reflect actual riskAdjust for site conditions, equipment, handling methods, and exposure durationOff-the-shelf COSHH templates used unchangedCOSHH Reg 6Frequency and DurationConsider level of exposureAssess how often and how long workers are exposed to substancesNo consideration of repeated or prolonged exposureCOSHH Reg 6Workplace ConditionsReflect real environmentVentilation, space, temperature, and layout considered in controlsControls not suited to actual workplaceCOSHH / HSW ActImplementation of ControlsEnsure controls are appliedSupervision and monitoring confirm controls are followed in practiceControls exist only within documentationCOSHH Reg 7A COSHH assessment only meets the required standard if it works in practice. It should clearly show how exposure is controlled, who is at risk, and what measures are in place to prevent harm. If those controls are not being followed, the assessment is not sufficient, regardless of how detailed it appears. Employers should be confident that their COSHH assessments reflect real working conditions and support how work is actually carried out. This is what regulators look for. Not perfect documentation, but evidence that risks are properly understood, controls are appropriate, and exposure to hazardous substances is being effectively managed. COSHH Control Measures in PracticeA COSHH assessment only has value if it leads to effective control of exposure. The focus is not on identifying risk alone, but on what is put in place to manage it. Control measures need to reflect how substances are actually used and how exposure occurs during work. In practice, this means applying a structured approach to control, supported by clear instructions and active supervision. Controls should be visible, understood, and consistently followed. Where they are not, the assessment itself becomes ineffective. The key test is simple: are the measures in place reducing exposure in real working conditions, not just on paper. AreaLegal ExpectationWhat This Means in PracticeCommon Failure PointRelevant RegulationElimination / SubstitutionPrevent exposure where possibleRemove hazardous substances or replace with less harmful alternativesHazardous substances retained without reviewCOSHH Reg 7Engineering ControlsControl exposure at sourceUse extraction systems, ventilation, enclosed processes, or isolationReliance on PPE instead of engineering solutionsCOSHH Reg 7Administrative ControlsManage how work is carried outSafe systems of work, clear procedures, restricted access, task planningProcedures not followed or not aligned with actual tasksCOSHH / HSW ActPersonal Protective Equipment (PPE)Provide PPE where risk remainsPPE used as last line of defence, suitable for task and properly maintainedPPE relied on as primary control measureCOSHH Reg 7 / PPE RegsStorage of SubstancesStore safely to prevent riskSegregation, secure storage, correct containers, clear identificationPoor storage leading to leaks, spills, or misuseCOSHH Reg 6Handling ProceduresControl risk during useSafe handling methods, minimising exposure during transfer or useInformal handling practices developing over timeCOSHH Reg 7Labelling and IdentificationEnsure substances are clearly identifiedClear labelling, hazard information available and understoodUnlabelled or incorrectly labelled containersCOSHH / CLP RegulationsExposure MonitoringMonitor where necessaryAir monitoring, health surveillance where exposure risk justifies itNo monitoring where exposure risk is significantCOSHH Reg 10Clear InstructionsProvide information and instructionWorkers understand risks, controls, and correct use of substancesInstructions unclear or not communicated effectivelyHSW Act / COSHHSupervisionEnsure controls are followedActive oversight to confirm controls are applied consistentlyControls drift over time without supervisionCOSHH / Management RegsControl measures are only effective if they are applied consistently and reflect how work is actually carried out. It is not enough to define controls within an assessment. Employers need to ensure those measures are in place, understood, and maintained through supervision and regular review. You should be able to see control on site or in the workplace. Substances are handled correctly, exposure is reduced, and workers understand what is expected of them. This is what demonstrates compliance in practice. Not the presence of control measures in a document, but clear evidence that they are being used and are working as intended. Reviewing, Maintaining, and Managing COSHH Over TimeCOSHH does not end once an assessment is completed. Workplaces change, processes evolve, and new substances are introduced over time. If assessments are not kept current, they quickly lose relevance. Maintaining COSHH means ensuring it continues to reflect how work is actually carried out, not how it was originally planned. In practice, this requires ongoing attention. Risks need to be revisited, controls checked, and arrangements updated as conditions develop. COSHH should sit alongside wider risk management, not separately from it. When it is actively maintained, it supports consistent control. When it is left unchanged, gaps begin to appear. When COSHH Must Be ReviewedCOSHH assessments should be reviewed whenever there is a change that could affect exposure to hazardous substances. This includes the introduction of new materials, changes to processes, or adjustments to how substances are used. Incidents, near misses, or signs of ill health should also trigger a review. The aim is to ensure that assessments remain accurate and controls remain effective. Where reviews are not carried out, risks can develop without being recognised. Over time, this leads to assessments that no longer reflect the reality of the workplace. Regular review is what keeps COSHH aligned with changing conditions. Integrating COSHH into Day-to-Day ManagementCOSHH should not sit in isolation from other health and safety arrangements. It needs to be integrated into risk assessments, training, and supervision so that controls are consistently applied. Workers should understand the substances they are using, the risks involved, and the measures in place to protect them. Supervision plays a key role in maintaining this link. It ensures that controls are followed and that any changes in how work is carried out are recognised early. When COSHH is embedded into daily activity, it becomes part of how work is managed, rather than a separate administrative task. Common COSHH Failures in PracticeA common issue is COSHH information becoming outdated. Assessments are completed, stored, and then not revisited as work changes. New substances may be introduced without assessment, or existing controls may no longer reflect how tasks are carried out. Another failure point is treating COSHH as a document rather than a process. Where this happens, controls exist on paper but are not applied in practice. This creates a gap between compliance and actual risk control. Maintaining COSHH requires ongoing attention, not just initial completion. COSHH as Ongoing Risk ManagementCOSHH should be viewed as part of a wider approach to managing risk. It supports how hazardous substances are controlled alongside other workplace risks, rather than operating separately. When maintained properly, it helps ensure that exposure remains controlled as work evolves. Employers should be able to demonstrate that COSHH arrangements are current, relevant, and applied in practice. This includes showing that assessments are reviewed, controls are maintained, and risks are understood by those carrying out the work. That is what defines effective COSHH management over time. Putting COSHH Into PracticeCOSHH is not about producing paperwork. It is about controlling exposure in a way that reflects how work is actually carried out. The assessment is only one part of that process. What matters is whether substances are being handled safely, whether exposure is understood, and whether controls are working in practice. Employers should be in a position where COSHH arrangements are clear, relevant, and easy to apply. That includes being able to recognise when an assessment is too generic, when it does not reflect the task, or when controls are no longer aligned with the way work is being done. Confidence comes from knowing that what is documented matches what is happening on the ground. Where COSHH is working properly, it is visible. Substances are managed correctly, controls are followed, and risks are kept under control as conditions change. Where it is not, the gap is usually between documentation and reality. THSP works with employers to close that gap. From carrying out COSHH assessments that reflect real working conditions, to supporting implementation through training, review, and ongoing advice, the focus is on making control work in practice. If you want confidence that your COSHH arrangements are effective, not just compliant, speak to THSP for a practical review and clear next steps. Frequently Asked Questions About COSHH AssessmentsWhat is the first step in a COSHH assessment?The first step in a COSHH assessment is identifying hazardous substances used, stored, or generated through work activities. This includes not only labelled chemicals, but also dusts, fumes, vapours, and by-products of processes. The focus should be on where exposure could occur, rather than simply listing substances present in the workplace. What is a COSHH assessment form?A COSHH assessment form is a structured document used to record how risks from hazardous substances are assessed and controlled. It typically includes details of the substance, how it is used, exposure routes, who may be affected, and the control measures in place. The form itself is not the assessment. Its value depends on whether it reflects real working conditions and supports effective control of exposure. What should a COSHH risk assessment include?A COSHH risk assessment should include:The hazardous substance and how it is usedHow exposure can occur (inhalation, skin contact, ingestion)Who may be exposed and how oftenThe level and duration of exposureControl measures in place, following the hierarchy of controlAny required PPE, monitoring, or health surveillanceClear instructions for safe use, handling, and storageThe key is that it reflects actual tasks and working conditions, not a generic template. How often should COSHH assessments be reviewed?COSHH assessments should be reviewed whenever there is a change that could affect exposure. This includes new substances, changes to processes, different working conditions, or following incidents and near misses. Even without obvious changes, assessments should be reviewed periodically to ensure they remain accurate and aligned with how work is carried out. What does a COSHH assessment cover?A COSHH assessment covers the risks to health from hazardous substances and how those risks are controlled. This includes identifying exposure routes, assessing who may be affected, and putting measures in place to prevent or adequately control exposure. It applies to all stages of work, including use, handling, storage, and disposal of substances, as well as any by-products created during processes.