Cylinder, Compressed Gas

A compressed gas cylinder is considered 'empty' if the pressure inside the cylinder equals or nearly equals atmospheric pressure. However, cylinders that held a poison, pesticide or other highly toxic gas may require triple-rinsing to be considered “empty.” To find out if the gas cylinder needs triple-rinsing, contact Department of Ecology at 425-649-7000. Never vent hazardous gases into the air to empty a gas cylinder.

If the cylinder pressure is equal to atmospheric but it held a poison, pesticide or other highly toxic gas that requires triple-rinsing, the cylinder is not empty. Instead of attempting to triple-rinse such a gas cylinder, send it unrinsed to a Hazardous Waste Disposal company with trained staff and facilities for rinsing. The rinsing liquids are also hazardous waste. For cylinders that do not require rinsing, these cannot be disposed to the garbage.