Ontario waste class 331 Gas bottles & cylinders holding pressurized gas.

Free, no account
Based on Ontario Regulation 347 and registration guidance
Nothing is stored

Ontario other wastes
Compressed gases and cylinders

Ontario group: compressed gases.

Compressed gases & their cylinders, from welding gas to propane bottles, in Ontario's group of compressed gases.

Is Ontario 331 hazardous waste?

Not from the code alone. Ontario 331 names the waste stream. Whether the waste is subject waste depends on its hazardous characterization or liquid-industrial status, and on the exclusions. The waste number also needs a primary characterization letter after the 3-digit class.

For subject waste, the generator enters the class-and-letter waste number in the waste details of the Ontario hazardous waste manifest. Ontario’s exclusions and shipment rules apply.

What does Ontario 331 cover?

Discarded compressed gases and their cylinders. Examples are methane or natural gas, nitrous oxide, nitric oxide, and propane or butane, including discarded cylinders. Whether it is hazardous is a separate decision under Ontario’s waste rules.

Rule: Registration guidance manual, Appendix A: Ontario waste classes

Is compressed gas waste Ontario 331 or another class?

Code	When it fits
331	The stream is discarded compressed gas and its cylinders.

When several characterizations apply, the registration flowchart picks the primary one. The 3-digit class doesn’t replace the flowchart or the exclusions.

Which wastes take Ontario 331?

Waste	When it’s 331
Waste compressed gases and cylinders	Gas left in the cylinder.
Methane (natural gas)	Gas left in the cylinder.
Nitrous oxide or nitric oxide	Gas left in the cylinder.
Propane	Gas left in the cylinder.
Butane	Gas left in the cylinder.

Which codes sit beside Ontario 331?

Code	What it is
321	Explosive production/detonation waste