The gases on this list are either on the Department of Transportation's Category 1 list, or the Linde Specialty Gases company's Group 6 - Very Poisonous list. These chemicals are highly toxic gases at ambient temperature and pressure. They have an extremely high potential for causing significant harm if not adequately controlled.
|Arsine||Boron trichloride||Chlorine pentafluoride|
|Chlorine trifluoride||Cyanogen||Cyanogen chloride|
|Germane||Hydrogen selenide||Nitric oxide|
|Nitrogen dioxide||Nitrogen trioxide||Nitrosyl chloride|
|Phosphorus pentafluoride||Selenium hexafluoride||Stibine|
|Sulfur tetrafluoride||Tellurium Hexafluoride||Tetraethyldithiopyrophosphate|
Guidance: Departments may choose to add other chemicals to the above list. For example, sulfur-containing compounds such as mercaptans can cause significant odor problems when used in the laboratory. Pre-approval of the conditions under which they can be used may prevent odor complaints.