High Hazard Gases

The University of Wisconsin–Madison is dedicated to providing a safe and healthy working environment for all faculty, staff, students and visitors. Cylinders containing compressed or liquefied gases pose a significant safety hazard if proper care is not taken in the storage, set-up, and use of the gases.

The University of Wisconsin–Madison by policy requires approval by the Environment, Health & Safety Department (EH&S) prior to both the initial purchase and initial use of the high-hazard gases falling into the categories listed below. Approval is not required for re-orders of gas cylinders as long as their use, procedures, quantity, and location have not changed.

This policy is designed to ensure that laboratory infrastructure is adequate for the use and storage of such gases. Additionally, the policy ensures that users have performed a hazard assessment, enacted appropriate engineering controls, and have received the necessary training prior to using the gases. It is the responsibility of the individual who intends to use a high-hazard gas to contact the Chemical Safety Office (within EH&S) prior to ordering.

The gases in the following hazard classes are subject to this policy:

• All gases that are designated by Global Harmonization System (GHS) classification as Category 1 or 2 for acute toxicity;
• All corrosive gases as designated by GHS, including both gases that are corrosive to the skin and/or corrosive to metal;
• All pyrophoric gases.

NOTES: Certain vendors require formal risk assessments prior to selling specific gases – some which are outside the above criteria. In these instances EH&S will work with the vendors and UW staff to ensure that the assessments are performed. Use of gas cylinders is also subject to various restrictions and regulations as outlined in the UW–Madison Campus Chemical Hygiene Plan.

This policy applies to the properties of the contents of cylinders taken as a whole, not the individual components. For example, a pure gas may have acute toxicity and be subject to this policy while a gas mixture containing a high percentage of an inert gas along with the same toxic gas may not be subject to this policy. Contact the Chemical Safety Office for additional information on which gases or gas mixtures may meet the above criteria.

Pyrophoric Gases

A pyrophoric substance is a chemical that will ignite spontaneously in air at a temperature of 130 degrees Fahrenheit (54.4 degrees C) or below. Pyrophoric gases (in addition to the Flame GHS pictogram) will have the H220 hazard statement “Extrememly flammable gas” or the H232 hazard statement “May ignite spontaneously if exposed to air.”

Example Pyrophoric Gases Include:

• Arsine (AsH₃)
• Diborane (B₂H₆)
• Dichlorosilane (SiH₂Cl₂)
• Phosphine (PH₃)
• Silane (SiH₄)
• Stibine (SbH₃)