Ep. 27: Understanding Flammable Liquids – It’s Not Just the Fire You See

When it comes to Class 3 Flammable Liquids, it’s not the liquid itself that burns — it’s the vapours. And once they’re in the air, the risk multiplies. 

In this episode, Patrick Gee breaks down: 

• Why flammable vapours pose the real danger 
• Flash point, flashback, explosive range and auto-ignition 
• The health risks of common flammable liquids like petrol, acetone, and benzene 
• How vapour exposure can affect workers — and the environment 
• What to look for in your Safety Data Sheet (SDS) 
• The right way to store, segregate, and secure flammable liquids 

Whether you're managing petrol, methylated spirits or solvents, this episode helps you go beyond the basics to understand the full risk — and what to do about it. 

🎧 Subscribe for more straight-talking advice on dangerous goods safety. 

Chapters

• 0:00 Introduction to Flammable Liquids
• 1:57 Understanding Fire Risks and Flashback
• 3:39 Health Hazards of Common Chemicals
• 4:54 Environmental Impacts and Concerns
• 5:31 Risk Reduction and Proper Storage
• 6:03 Conclusion and Episode Wrap-Up

Transcript

Speaker 1: 0:06

G'day and welcome to Chemical Safety at Work, the podcast that helps you make sense of dangerous goods risks in the workplace and gives you practical steps to stay compliant, stay safe and protect your people. I'm Patrick Gee and today we're talking about Class 3 flammable liquids. Now you probably already know that flammable liquids are dangerous substances, but did you know? It's not actually the liquid that burns, that's right, it's the vapors. And when those vapors mix with air and meet an ignition source, that's when you've got a serious fire risk. But that's just the beginning to. To properly manage these substances, you also need to understand whether the chemical is explosive, volatile, corrosive, toxic or even carcinogenic. In this episode we'll break down the risks fire flashback, health hazards, environmental impacts and, most importantly, what you can do to control them. Let's crack in. When we're assessing the risk of fire, we've got to start with a few key terms Flammable range, volatility, flashpoint and auto-ignition temperature. All of this can be found in the chemical's safety data sheet, the SDS. Don't guess, check it every time. So what's a flashpoint? Don't guess, check it every time. So what's a flashpoint? That's the lowest temperature at which a liquid can produce enough vapour to ignite and continue to burn. In Australia, any liquid with a flashpoint below 60 degrees is classified as a dangerous good. The lower the flashpoint, the higher the fire risk. These chemicals can ignite at normal room temperatures, so they need to be kept away from ignition sources like heat, flames, sparks and even static discharge. Now here's a big one flashback. When you open a container of flammable liquid, vapors can escape and travel through the air. These vapors are heavier than air, so they can spread across a floor for hundreds of metres. If those vapours meet a spark, the fire can travel back along the vapour trail to the source. That's a flashback and it's extremely dangerous. Then there's auto-ignition the temperature at which a chemical will ignite on its own without any spark or flame, and explosive range the temperature and concentration range where the chemical becomes capable of exploding. The key takeaway here store flammable liquids in proper safety cabinets, ones that meet Australian standards, to keep them below their ignition range and prevent vapour build-up.

Speaker 1: 2:44

Flammable liquids aren't just fire risks. Many of them are harmful to human health. Their vapours can irritate the skin, damage organs and, in some cases, cause long-term illness or cancer. Let me give you a few examples Petrol it's a skin irritant, carcinogenic, mutagenic. Long-term exposure can damage your heart, liver and kidneys. Diesel is also a skin irritant and suspected carcinogen. Methylated spirits can irritate eyes and skin and frequent exposure may lead to dryness or cracking. Mineral turpentine is harmful if inhaled and respiratory issues are common. Acetone can cause dizziness, drowsiness, serious eye irritation and organ damage with prolonged exposure. Kerosene affects the nervous system over time, and benzene this one's especially toxic, known to be carcinogenic and mutagenogenic. That's why proper risk assessments are critical.

Speaker 1: 3:46

You've got to consider not just what the chemical is, but how long workers are exposed, how much vapor is present and what the ventilation's like. If you're using flammable liquids, you also need to think about the environment. Spills, leaks and emissions can have serious consequences, not just for your site, but for your community and local ecosystems. Many flammable liquids are highly toxic to aquatic life and even small leaks can contaminate drinking water. Some release carcinogenic emissions. That impacts not only your workers but the air quality around your site.

Speaker 1: 4:23

The takeaway here make sure you check sections 11 and 12 of the SDS. That's where you'll find information on toxicological and ecological risks, so don't overlook it. So how do we reduce all these risks? Well, proper storage is the answer, and that means using compliant flammable liquid cabinets, segregating flammable liquids from ignition sources containing spills with bunding or closed decanting stations, keeping chemicals out of drains, sewers and waterways and preventing unauthorized access with secure storage setups. By putting the right systems in place, you're not just meeting your compliance obligations, but protecting your people, your community and your environment.

Speaker 1: 5:10

That's it for chemical safety at work for this week. If you found this helpful, share it with your team and don't forget to subscribe for more practical advice on handling dangerous goods safely and responsibly. If you're ever unsure about a chemical or need expert support, remember the SDS is your starting point and if you need more than that, get in touch with a qualified dangerous goods consultant. Thanks for listening. We love to hear from our listeners, so send us a message and let us know if there are any topics you'd like us to do a deep dive on. Stay safe, and I'll catch you next time.