The Purchase and Initial Use of High-Hazard Gas Cylinders
University Policy
- Scope:
This policy applies to all UW–Madison faculty, staff, students and part-time employees that use compressed gas cylinders containing high-hazard gases in university facilities, including research and teaching laboratories.
- Policy:
Background
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.
Policy
The University of Wisconsin–Madison 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 has not changed. This policy is designed to ensure that the 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 Chemical Safety Office can be contacted via phone at 265-5700 or via email at chemsafety@fpm.wisc.edu.
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.
Appendix 1 of this document lists some of the most common hazardous gases, by class, which fit the above criteria. 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.
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 and Policy.
Additional Information
Information on the classes of gases subject to this policy is given below.
Gases with Acute Toxicity
Gases designated as Category 1 for acute toxicity have a median lethal concentration (LC50) in air of 100 parts per million (ppm) or less by volume based on a 4-hour animal exposure. Category 2 gases have a LC50 greater than 100 ppm and equal to/or greater than 500 ppm. When experimental values are taken from tests using a 1-hour exposure, they can be converted to a 4-hour equivalent by dividing the 1-hour value by a factor of 2 for gases and vapors. Safety Data Sheets for gases meeting these criteria (in addition to the Health Hazard GHS pictogram) will have the following hazard statement: “Fatal if Inhaled”
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 following hazard statement: “Catches fire spontaneously if exposed to air”
Corrosive Gases
Gases designated as a skin corrosive cause visible destruction of, or irreversible alterations in, living tissue by chemical action at the point of contact, typically based on 4-hour (or less) animal exposure studies. Gases designated as corrosive to metal have a corrosion rate on either steel or aluminum surfaces exceeding 6.25 mm per year at a test temperature of 55°C (131°F) when tested on both materials. Corrosive gases (in addition to the Corrosion GHS pictogram) will have the following hazard statements: “Causes severe skin burns and eye damage” or “May be corrosive to metals”
More in-depth information on the Global Harmonization System can be found on the Occupational Safety and Health Administration’s website.
- “A Guide to the Globally Harmonized System of Classification and Labeling of Chemicals”
- The Appendices to 29 CRF 1910.1200 (Hazard Communication) provide detailed information on the classifications. See Appendix A for information on acute toxicity and corrosion classes and Appendix B on pyrophoric materials.
Appendix 1. List of Pure Gases Subject to this Policy
Below is a list of common gases that fall into the three defined hazard classes which are subject to this policy. The list should not be construed as a complete list. Note that some gases fall into more than one class.
Corrosive Gases
- Ammonia (NH3)
- Boron Trifluoride (BF3)
- Boron Trichloride (BCl3)
- Chlorine (Cl2)
- Chlorine Dioxide (ClO2)
- Chlorine Trifluoride (ClF3)
- Dichlorosilane (SiH2Cl2)
- Fluorine (F2)
- Hydrogen Bromide (HBr)
- Hydrogen Chloride (HCl)
- Hydrogen Fluoride (HF)
- Methylamine (CH3NH2)
- Nitric Oxide (NO)
- Sulfur Dioxide (SO2)
- Sulfur Tetrafluoride (SF4)
- Trimethylamine (N(CH3)3)
Toxic gases
- Arsine (AsH3)
- Boron Trifluoride (BF3)
- Chlorine (Cl2)
- Chlorine Dioxide (ClO2)
- Chlorine Trifluoride (ClF3)
- Diborane (B2H6)
- Dichlorosilane (SiH2Cl2)
- Formaldehyde (CH2O)
- Fluorine (F2)
- Germane (GeH4)
- Hydrogen Cyanide (HCN)
- Hydrogen Selenide (H2Se)
- Hydrogen Sulfide (H2S)
- Nickel Carbonyl [Ni (CO)4]
- Nitrogen Dioxide (NO2)
- Phosgene (COCl2)
- Phosphine (PH3)
- Stibine (SbH3)
- Sulfur Tetrafluoride (SF4)
Pyrophoric Gases
- Arsine (AsH3)
- Diborane (B2H6)
- Phosphine (PH3)
- Silane (SiH4)
- Stibine (SbH3)
- External References: