A Pleasant Smell Says Nothing About Explosion Safety
Vanilla. Lemon. Peppermint. Orange. Lavender.
Most people associate these fragrances with food, cosmetics, cleaning products or perfumes. Explosion safety is rarely the first thing that comes to mind.
Yet this is precisely where a dangerous assumption can arise.
Across the food, pharmaceutical, cosmetics and fine chemical industries, flavourings and fragrances are handled every day. Many of these products contain volatile organic compounds or flammable solvents such as ethanol, isopropyl alcohol or other organic substances. However, a pleasant smell tells us nothing about the physical properties of a substance or the risk that an explosive atmosphere may develop during storage, mixing, dosing, processing or cleaning operations.
Explosion safety therefore does not assess a substance by its smell, but by its physical and chemical properties. Vapour pressure, flash point, explosive limits, minimum ignition energy, auto-ignition temperature and the actual process conditions determine whether an explosive atmosphere can occur. It is this combination of factors—not the fragrance—that defines the explosion risk and the protective measures required.
This also explains why the same substance can lead to completely different risk assessments in different processes. A small quantity of solvent inside a sealed container presents a different hazard from the same solvent when it is heated, atomised, sprayed or intensively mixed. Ventilation, process pressure, release characteristics and the frequency of vapour emissions all influence the final engineering assessment.
This is exactly why EN IEC 60079-10-1 for explosive gas atmospheres and EN IEC 60079-10-2 for combustible dust atmospheres do not provide lists of "safe" or "dangerous" substances. Instead, these standards establish a structured engineering methodology to determine under which operating conditions an explosive atmosphere may occur. The focus is not on the name, smell or intended application of a substance, but on the interaction between its physical properties, the process conditions and the potential sources of release.
For designers, operators, HSE professionals and asset owners, this is an important lesson. Familiarity should never replace technical assessment. The substances used every day deserve the same objective evaluation as those universally recognised as hazardous. Safety Data Sheets (SDS), process parameters and substance properties should always form the basis for hazardous area classification, equipment selection and safe operational management.
Within the European Union, this engineering approach supports compliance with the ATEX Workplace Directive (1999/92/EC), which requires employers to assess and control explosion risks. In the United Kingdom, equivalent duties are established under the Dangerous Substances and Explosive Atmospheres Regulations (DSEAR). In both jurisdictions, explosion protection is based on understanding the actual hazards presented by the process—not on assumptions created by appearance, familiarity or smell.
Perhaps this is the most important conclusion. A pleasant fragrance says nothing about explosion safety. The human sense of smell is neither a safety device nor a risk assessment tool. Explosion safety begins where assumptions end and engineering knowledge begins. It is not the smell of a substance that determines the risk, but its properties and the conditions under which it is used.
References
- ATEX Directive 2014/34/EU
- ATEX Workplace Directive 1999/92/EC
- UK Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR)
- EN IEC 60079-10-1:2021 – Explosive Atmospheres – Classification of Areas – Explosive Gas Atmospheres
- EN IEC 60079-10-2:2026 – Explosive Atmospheres – Classification of Areas – Combustible Dust Atmospheres
- EN 1127-1 – Explosion Prevention and Protection
- Regulation (EC) No 1907/2006 (REACH)
- Regulation (EC) No 1272/2008 (CLP)
- Safety Data Sheets (SDS)
- European Chemicals Agency (ECHA)