What is the difference between DSEAR and ATEX?

Author picture

Ryan Lloyd-Davies is CEO and Technical Director of ORBIS Environmental Ltd and the company’s Principal DSEAR Consultant. With around 20 years’ experience in health, safety and compliance, Ryan specialises in DSEAR, ATEX, hazardous area classification, fire and explosion risk, flammable substances and combustible dusts. He has worked across MOD, aviation, fuel, chemical, NHS, prison, manufacturing and emergency response environments. His approach is practical, technically robust and commercially aware, helping clients achieve proportionate compliance that genuinely fits their site and resources.

Many people get confused between DSEAR and ATEX, and it’s easy to see why — they’re closely linked but serve different purposes.

DSEAR, which stands for the Dangerous Substances and Explosive Atmospheres Regulations, is the UK legislation that requires businesses to carry out risk assessments wherever flammable substances are present. Its main purpose is to make sure workplaces are assessed for the presence of dangerous substances, the risks are clearly understood, and that hazardous areas are properly classified.

Once those hazardous zones are identified, ATEX comes into play. ATEX refers to European directives that cover equipment used in explosive atmospheres: Directive 137 (the worker protection directive) and Directive 100 (the equipment directive). In simple terms, ATEX is about making sure that any electrical or mechanical equipment used in those hazardous zones is safe and won’t ignite an explosive atmosphere.

To put it into context, imagine you’re mixing solvents that give off flammable vapours. Those vapours spread into the surrounding air, creating an invisible “bubble” of risk. That bubble might extend one, two, or three metres around the process. Inside that bubble, only ATEX-rated equipment can be used. This ensures that if equipment fails, it won’t spark, overheat, or cause an ignition.

So, the difference can be summed up like this: DSEAR is the process of assessing the risks and defining the hazardous areas, while ATEX ensures that any equipment inside those areas is designed not to trigger an explosion.