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DSEAR Risk Assessments: When Are They Needed And What Should They Cover?

DSEAR is one of those areas of health and safety that many businesses either misunderstand or overlook completely.

Some assume it only applies to chemical plants, fuel depots or major industrial sites. Others think it is covered automatically because they already have COSHH assessments, fire risk assessments or safety data sheets in place.

In reality, DSEAR can apply to a much wider range of workplaces.

If your business stores, uses, produces or handles substances that could create a fire, explosion, pressure or metal corrosion risk, you may need to assess those risks under DSEAR. That can include obvious substances such as petrol, solvents, LPG and flammable gases, but also less obvious risks such as combustible dusts, aerosols, vapours, gases under pressure and certain substances corrosive to metals.

The purpose of a DSEAR risk assessment is not simply to create another document. It is to identify whether dangerous substances could cause harm and to make sure suitable controls are in place before something goes wrong.

What Does DSEAR Mean?

DSEAR stands for the Dangerous Substances and Explosive Atmospheres Regulations 2002.

The Health and Safety Executive explains that dangerous substances can put people’s safety at risk from fire, explosion and corrosion of metal. DSEAR places duties on employers and the self-employed to protect employees and others who may be affected by work activities. The HSE’s main guidance on Dangerous Substances and Explosive Atmospheres Regulations is the key starting point for understanding those duties.

In simple terms, DSEAR is concerned with substances and atmospheres that could create sudden, serious safety risks.

That includes:

  • fire
  • explosion
  • energetic reactions
  • pressurised releases
  • corrosion of metal where it creates a safety risk

This makes DSEAR different from COSHH, although the two can overlap.

COSHH is mainly concerned with risks to health from exposure to hazardous substances. DSEAR is mainly concerned with safety risks from dangerous substances, particularly fire and explosion.

For example, a solvent may need to be assessed under COSHH because inhaling vapour could harm health. The same solvent may also need to be assessed under DSEAR because the vapour could ignite.

Why DSEAR Is Often Missed

DSEAR is often missed because many businesses do not think of themselves as using “dangerous substances”.

They may think that because they only store small quantities, or because the substance is commonly used, the risk is not significant. They may also assume that if the product is bought from a reputable supplier, the risk has somehow already been dealt with.

That is not how DSEAR works.

The question is not whether the substance is familiar. The question is whether it could create a relevant safety risk in the way it is stored, used, mixed, handled, transferred, heated, sprayed, cleaned up or disposed of.

A business may need to think about DSEAR if it uses or stores:

  • petrol or diesel
  • LPG
  • acetylene
  • oxygen cylinders
  • flammable paints, thinners or solvents
  • aerosols
  • cleaning chemicals
  • adhesives
  • resins
  • alcohol-based products
  • wood dust
  • flour dust
  • metal powders
  • welding gases
  • battery charging areas
  • pressurised gases
  • substances corrosive to metals

The list is not exhaustive. What matters is the risk created by the substance and the work activity.

DSEAR Is Not Just For Heavy Industry

It is easy to picture DSEAR as something that only affects large factories or high-hazard sites.

Those workplaces may certainly need detailed assessments, but DSEAR can also be relevant in more ordinary commercial environments.

Examples may include:

  • workshops using flammable paints or solvents
  • garages storing fuels, oils and aerosols
  • manufacturers creating dust through cutting, sanding, milling or mixing
  • food businesses handling flour or other combustible dusts
  • laboratories using flammable liquids or gases
  • facilities using LPG cylinders
  • warehouses storing dangerous goods
  • cleaning operations using flammable products
  • premises with battery charging areas
  • sites using welding gases
  • businesses storing pressurised gas cylinders

The workplace does not have to look dramatic for the risk to exist.

Small amounts of flammable vapour in the wrong location can create a serious fire or explosion risk. Dust that appears harmless can become dangerous if it becomes airborne in the right concentration. Gas cylinders that are not properly stored or managed can create pressure, fire or explosion risks.

This is why a sensible DSEAR assessment starts with the actual work, not assumptions about the type of business.

What Counts As A Dangerous Substance?

Under DSEAR, dangerous substances are not limited to products with obvious warning labels.

A dangerous substance may be a liquid, gas, vapour, dust, mist or solid. It may be present as a product being used intentionally, a by-product of a process, or something created during work activity.

This is important because some businesses focus only on the substances they buy, rather than the substances or atmospheres created by the work.

For example:

  • cutting, sanding or grinding may create combustible dust
  • spraying can create flammable mist or vapour
  • heating can increase vapour production
  • decanting liquids can release flammable vapours
  • leaks can create explosive atmospheres
  • poor ventilation can allow vapours or gases to accumulate
  • chemical reactions can generate heat, gas or pressure
  • charging batteries can release hydrogen

A safety data sheet can help identify hazards, but it is not the assessment itself.

The business still needs to understand how the substance is used on site, where it is stored, who may be exposed, what could ignite it, and what controls are needed.

What Changed In 2015?

DSEAR has existed since 2002, but the scope was widened in 2015.

HSE guidance explains that, since 2015, DSEAR also covers risks caused by gases under pressure and substances that are corrosive to metals.

This matters because some businesses still think of DSEAR only in terms of classic fire and explosion risk.

Pressurised gases can create serious safety risks if cylinders are damaged, poorly stored, exposed to heat, incorrectly handled or involved in a fire. Substances corrosive to metals may create risks where they can damage containment systems, pipework, structures or equipment in a way that could lead to a dangerous failure.

A modern DSEAR assessment should therefore consider more than just whether a substance can catch fire.

It should look at the full range of relevant dangerous substance risks in the workplace.

What A DSEAR Risk Assessment Should Consider

A DSEAR risk assessment should be specific to the workplace and the activities being carried out.

It should consider the dangerous substances present, how they are used, how they are stored, how they could be released, and how people could be harmed.

A good assessment should normally consider:

  • what dangerous substances are present
  • the quantity of each substance
  • where substances are stored
  • how substances are handled, used or transferred
  • whether vapours, mists, gases or dusts may be produced
  • whether explosive atmospheres could occur
  • ignition sources
  • ventilation
  • containment
  • segregation
  • emergency arrangements
  • maintenance activities
  • cleaning and spill response
  • training and supervision
  • who may be affected, including contractors and visitors
  • whether hazardous areas need to be classified into zones
  • whether equipment is suitable for use in those areas

The assessment should not simply list substances. It should explain the risk and the controls.

For example, it is not enough to note that flammable liquids are stored in a cabinet. The assessment should consider the quantity stored, whether the cabinet is suitable, whether containers are kept closed, whether incompatible materials are segregated, whether ventilation is adequate, how spills are managed, and whether ignition sources are controlled.

Why Ignition Sources Matter

DSEAR is not only about the dangerous substance. It is also about what could ignite it.

A flammable vapour only becomes a fire or explosion risk if the right mixture with air is present and an ignition source is available. That means ignition control is a central part of DSEAR risk management.

Potential ignition sources may include:

  • naked flames
  • hot work
  • sparks
  • static electricity
  • electrical equipment
  • hot surfaces
  • smoking
  • mechanical friction
  • vehicle movements
  • portable heaters
  • battery charging
  • unsuitable tools or equipment

This is where some businesses underestimate the risk.

They may store flammable products correctly most of the time, but then carry out maintenance, cleaning, charging, grinding, welding or temporary works nearby without considering how the risk has changed.

A good DSEAR assessment should consider normal operations and reasonably foreseeable abnormal situations, such as leaks, spills, equipment failure, maintenance and emergency conditions.

Hazardous Area Classification And Zoning

In some workplaces, DSEAR requires areas where explosive atmospheres may occur to be classified into zones.

Zoning is used to identify how likely it is that an explosive atmosphere may be present and for how long. This then helps determine what equipment and precautions are suitable in those areas.

For example, areas may need to be classified where flammable gases, vapours, mists or combustible dusts could create an explosive atmosphere.

Not every business using a flammable substance will automatically need complex zoning drawings. The need depends on the substance, quantity, process, ventilation, release potential and workplace layout.

However, where zoning is required, it needs to be done properly.

Poor zoning can create two problems. If the risk is underestimated, unsuitable equipment or controls may be used in dangerous areas. If the risk is exaggerated, the business may face unnecessary cost and complexity.

This is a good example of why competent advice matters. DSEAR assessments need to be proportionate, but they also need to be technically sound.

Common DSEAR Mistakes

Many DSEAR problems are not caused by businesses deliberately ignoring risk. They are caused by misunderstanding what needs to be assessed.

Common mistakes include assuming that COSHH assessments are enough, relying only on safety data sheets, failing to consider vapours or dusts, storing excessive quantities of flammable substances, overlooking ignition sources, ignoring maintenance activities, and failing to review changes in process or storage.

Other common issues include poor segregation, inadequate ventilation, unsuitable electrical equipment, lack of spill arrangements, poor cylinder storage, weak contractor control and lack of employee training.

A particularly common weakness is failing to consider how people actually use substances day to day.

For example, a flammable liquid may be stored correctly in theory, but staff may leave containers open during use. A product may be decanted into unsuitable containers. Aerosols may be stored near heat. Dust may accumulate on surfaces. Gas cylinders may be left unsecured. Waste materials may build up in work areas.

These are practical issues, not just paperwork issues.

The Link Between DSEAR And Fire Risk Assessment

DSEAR and fire risk assessment are closely linked, but they are not the same thing.

A general fire risk assessment considers fire risks in the workplace, including means of escape, fire detection, alarms, extinguishers, emergency lighting, fire doors, training and emergency procedures.

A DSEAR assessment focuses specifically on risks from dangerous substances and explosive atmospheres.

In many workplaces, the two should inform each other.

If dangerous substances are stored or used on site, the fire risk assessment should not ignore them. Equally, a DSEAR assessment should consider how fire safety arrangements would work if an incident occurred.

For example, the assessment may need to consider whether substances are stored away from escape routes, whether fire doors are protected from damage, whether extinguishers are suitable, whether emergency arrangements are understood, and whether contractors carrying out hot works could introduce additional risk.

The important point is that DSEAR should not sit in isolation. It should form part of the wider health and safety and fire safety management system.

Can A Business Complete Its Own DSEAR Assessment?

In some low-risk situations, a business may be able to complete a basic DSEAR assessment internally, provided it has the necessary competence.

For example, where small quantities of low-risk flammable products are stored and used in a straightforward way, internal assessment may be realistic.

However, external support is often sensible where the risks are more complex.

That may include situations involving:

  • larger quantities of flammable substances
  • flammable vapours in enclosed spaces
  • combustible dusts
  • spraying processes
  • gas cylinders or pressure systems
  • battery charging areas
  • poor ventilation
  • hazardous area classification
  • ATEX-rated equipment questions
  • manufacturing processes
  • hot work
  • chemical reactions
  • unclear or outdated arrangements

The key issue is competence.

A DSEAR assessment needs to be carried out by someone who understands the substances, the work activities, the potential ignition sources and the control measures needed. Guesswork is not enough.

What Good DSEAR Controls Look Like

DSEAR controls should aim to eliminate or reduce risk so far as reasonably practicable.

In practice, that may involve reducing the quantity of dangerous substances stored, substituting less hazardous products, improving ventilation, using suitable storage cabinets, segregating incompatible materials, controlling ignition sources, improving housekeeping, preventing leaks and spills, and ensuring suitable emergency arrangements.

Controls may also include:

  • keeping containers closed when not in use
  • using suitable containers and labels
  • storing cylinders securely
  • keeping flammable substances away from heat and ignition sources
  • using appropriate electrical equipment
  • controlling static electricity
  • maintaining equipment
  • managing hot work
  • training employees
  • supervising higher-risk activities
  • inspecting storage areas
  • reviewing changes before they are introduced

The right controls depend on the risk.

A practical assessment should therefore lead to a prioritised action plan, not just a list of theoretical recommendations.

Why Reviewing DSEAR Matters

A DSEAR assessment should not be treated as a one-off exercise.

It should be reviewed when there are significant changes, such as new substances, new processes, changes in storage quantities, building alterations, new equipment, changes in ventilation, incidents, near misses or changes in how work is carried out.

It should also be reviewed if the business discovers that controls are not being followed or are no longer effective.

This is important because DSEAR risks can change gradually.

A business may start by storing small quantities of a flammable product, then increase stock levels over time. A room may become more crowded. Ventilation may be altered. A new process may create vapour or dust. A maintenance task may introduce ignition sources. A contractor may bring substances or equipment onto site.

If the assessment is not reviewed, the business may be relying on an outdated view of the risk.

What Businesses Should Do Next

If you are unsure whether DSEAR applies to your workplace, start by identifying the substances and processes that could create fire, explosion, pressure or corrosion risks.

Look at what is stored, what is used, what is produced and what may be released during normal or abnormal activities.

Then consider whether the existing controls are enough.

Ask:

  • Do we know what dangerous substances are present?
  • Are they stored in suitable quantities and locations?
  • Could vapours, gases, mists or dusts be produced?
  • Are ignition sources controlled?
  • Is ventilation adequate?
  • Are employees trained?
  • Are emergency arrangements suitable?
  • Have changes been reviewed?
  • Do we need competent support?

If you cannot answer those questions confidently, it may be time to review your arrangements, including finding out more about our expertise in DSEAR risk assessments.

Final Thought

DSEAR is often overlooked because businesses do not always recognise when dangerous substance risks exist.

But the consequences of getting it wrong can be severe. Fire, explosion, pressure release and related incidents can cause serious injury, death, property damage, business interruption and enforcement action.

A good DSEAR risk assessment helps prevent that by identifying the substances, activities and conditions that could create danger, then setting out practical controls to manage the risk.

It should be specific, proportionate and based on how the workplace actually operates.

Most importantly, it should help the business understand the risk clearly enough to do something about it.

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