Open a 50 gallon drum safely by checking for built-up pressure first, then venting it slowly from the side before removing the bung or lid.
Opening a 50 gallon drum carelessly can turn a routine task into a dangerous one. Drums that have been sealed, stored, or exposed to temperature changes can build up significant internal pressure—and that pressure is the leading cause of injuries. The safe process comes down to a few non-negotiable steps: inspect, identify, vent slowly, and never stand directly over the opening.
Check the Drum Before You Touch a Wrench
Before opening anything, look the drum over completely. You are checking for bulging, swelling, leaks, heat, or hissing sounds—all of which indicate the drum is pressurized.
If the drum is visibly swollen, is hissing, or feels hot, stop. Do not crack the bung yet. These signs mean you need a higher level of control, up to and including remote mechanical opening.
Why Do Sealed Drums Build Up Pressure?
Several everyday conditions create pressure inside a sealed drum. Temperature swings are the most common—a drum stored in the sun or near a heat source will have its contents expand. Chemical reactions between the contents and residual moisture can generate gas, and volatile liquids can simply evaporate, creating vapor pressure inside the sealed head.
The first release of that pressure should always be slow and controlled, with your body out of the line of fire.
The Step-by-Step Opening Sequence That Works
Once the drum passes your inspection and you are confident pressure is not extreme, follow this sequence carefully. The two governing principles are relieve pressure safely and keep yourself out of the path of any unexpected release.
- Verify the contents. Check the label and the Safety Data Sheet (SDS) before opening anything. If the contents are unknown, OSHA’s position is clear: treat the drum as hazardous until you identify what is inside.
- Put on the right PPE. Use gloves, eye protection, and any other gear called for by the worksite hazard assessment and the SDS.
- Position yourself to the side. Stand beside the drum, not directly over the bung or lid. The top of the drum is the most dangerous place to be if the closure releases suddenly.
- Crack the closure slowly. Use the correct bung wrench for the drum type.
- Let the pressure escape slowly. Open the bung just enough to hear any hiss. Let the gas vent fully before you remove the bung completely or lift the lid.
- Listen for the success cue. When you hear pressure equalize and the hissing stops, it is safe to remove the closure completely.
If the drum hisses loudly, leaks around the threads, or shows any sign of violent release, back away and use a remote method instead of your hands.
When Hand-Opening Is Not Safe Enough
Some drums simply cannot be opened by hand safely. If pressure cannot be relieved remotely, shielding should be placed between the worker and the drum. The accepted methods include a pneumatic impact wrench or a hydraulic penetration device—both let you open or puncture the drum while standing at a distance.
For manual relief when you have no choice, That barrier is your last line of defense, and it should be in place before you approach the bung.
The type of drum matters too. Never try to pry the lid off one of those.
| Hazard Sign | Risk It Signals | Correct Response |
|---|---|---|
| Bulging or swollen drum | High internal pressure | Do not open by hand; use remote methods |
| Hissing when touched | Gas escaping under pressure | Stop; reposition to the side; vent slowly |
| Heat on the drum surface | Expansion or active reaction | Move away; cool or isolate before opening |
| Unknown contents or no label | Potential hazardous material | Treat as hazardous; check SDS before proceeding |
| Empty but sealed drum | Residual vapor pressure | Open with the same caution as a full drum |
There is one more hazard to manage: static electricity. That means no impact tools unless they are rated for the environment.
If you are working in a site that handles hazardous waste drums, That is a different process from simply opening a drum, but it is worth knowing before you start.
If you need to buy the right container for your work, see our roundup of the best 50 gallon drum options on the market today.
Common Mistakes That Cause Drum-Opening Injuries
Nearly every drum-related injury traces back to one of a handful of repeated errors. Skipping the pressure check is the most common—people assume the drum is safe because it looks fine. Standing directly over the bung is a close second. The correct tools matter too: a hammer, chisel, or pry bar has no place here. Use the right bung wrench and nothing else. Finally, never assume an ’empty’ drum is safe, and never cut or drill a drum without first confirming what is inside.
FAQs
What tools do I need to open a 50 gallon drum?
A standard bung wrench for the drum’s plugs, and for flammable contents, a non-sparking version. For sealed closed-head drums, remove the bung caps before attempting anything else. For open-top drums, you need the correct lid-bolt tool, not a pry bar. Remote opening tools like a pneumatic impact wrench are only needed when pressure is suspected.
How long should I wait after cracking the bung before removing it?
Wait until the hissing stops completely. Pressure can equalize in seconds or take several minutes depending on the contents and how much gas is trapped. There is no fixed time—the cue is silence. Once the hiss dies out, you can remove the bung fully and proceed. If you ever stop hearing hissing but fluid starts to bubble at the threads, stop and back away.
Is a 50 gallon drum the same as a 55 gallon drum?
In practical terms, yes. The standard industrial drum in the US is the 55-gallon size, and most people casually call it a “50 gallon drum.” The opening procedure in OSHA and DOE guidance applies identically to both sizes, and the pressurization risks are the same. The safety steps above work for any sealed metal drum you encounter.