Managing Health and Safety Risks of Harmful Gas Vapours – Part 3

Managing Health and Safety Risks of Harmful Gas Vapours – Part 3

Ensuring Safe Installation of Safety Mechanisms

There are various standards which assist with the employment of safety systems. For example, from the Energy Institute, American Petroleum Installation, specific Harmonised standards for certain applications, and international standards for functional safety such as IEC 61511. The majority of these will require a Process Hazard Assessment technique to be used such as a Hazard and Operability Study (HAZOP). The reason these are commonly employed is that it is a methodical and systematic means to identify and assess potential hazards associated with the design, construction, and operation of processes. The methodology is particularly useful for identifying where there is a non-obvious causal link between failures and where modifications are required for safeguards to protect against common cause failure.

Any scenarios which are deemed to present considerable risk to people, plant, or the environment can be further analysed using techniques such as Layer of Protection Analysis (LOPA). This study is used to determine the functional safety requirements of protective systems, such as those mentioned in the HSE bulletin, outlining the required reliability, functionality, and independence of the safety-related system from other control systems.


The consequences of failure to manage the health and safety risks of leaks of harmful substances can be profoundly serious. Beyond the immediate and often long-term risks to health and safety, failures can result in legal claims, prosecution, reputational harm, and employee concerns impacting recruitment and retention of personnel and productivity. Incidents involving leaks of toxic substances can also lead to environmental contamination and costly cleanup requirements.

When COMAH applies, it mandates the creation of a Safety Case which takes account of the design of the establishment, its surroundings, associated hazards, and risks. This requires a methodical consideration of risk controls and mitigation measures. Whilst not mandated for those not regulated by COMAH, a similar approach, including an assessment of the consequences of substance exposure may nevertheless assist in identifying relevant hazards and managing potential risk.

Effective risk management of the process, following COSHH, and ideally using a HAZOP as part of your risk assessment, will help to identify risks that cannot be eliminated.

Your risk assessment should identify reasonable and proportionate risk management controls for those residual risks taking account of the hazardous properties of the substance, information on health effects, the level, type, and duration of possible exposures and following the hierarchy of control.  You then need to implement and monitor the continued efficacy of those measures and review them periodically as well as following any incident or change to process.


Tristan Pulford | Sohail Khan | Sue Dearden

If you need further information or advice on the effectiveness of your engineered harmful substance controls please contact Tristan Pulford: [email protected] : 01530412777 

We can audit the controls in place in your workplace and assist in identifying where there are gaps in measures in place (as well as solutions).

Tristan is a chartered mechanical and process safety engineer and is Finch Consulting’s Capability Director. Sohail is a chemical engineer experienced in process safety management. Sue is a Solicitor at Finch Consulting specialising in Health and Safety.

Finch is a leading risk management consultancy, working worldwide with blue-chip clients in multiple sectors.

As a “critical partner” to our clients, we provide confidence to be a better business by helping identify, manage and mitigate risks associated with engineering, health and safety, and regulatory compliance. This is delivered through three core areas: Asset Management, Health & Safety Management and Process Safety Management.


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