CGA’s C-7 Publication Provides Essential Tool for Hazardous Materials Communication in Compressed Gas Industry

July 29, 2020

The recently revised safety standard CGA C-7, Guide to Classification and Labeling of Compressed Gases, includes precautionary labels and markings developed by the compressed gas industry for use on containers of compressed gases, cryogenic liquids, and other hazardous materials for the purpose of identifying the contents; warning of principal physical, health, and environmental hazards; and providing appropriate precautionary information.

In April 2020, the Compressed Gas Association (CGA) issued the 11th edition of CGA C-7, which provides illustrative labels for more than 120 gases and liquids, grouped according to the primary product hazard.


In order to meet the specific labeling and marking needs of the compressed gas industry, CGA C-7 follows the methods of preparing label information and providing appropriate precautionary information established by the Globally Harmonized System of Classification and Labelling of Chemicals (GHS), as allowed by the U.S. Occupational Safety and Health Administration (OSHA).

Established by the United Nations, GHS provides a means of hazardous classification and communication via labels, pictograms, and consistent hazard language on a global basis. Internationally, competent authorities may adopt the GHS in whole or in part and may also require additional information on labels.

CGA C-7 follows the requirements stipulated in Title 29 of the U.S. Code of Federal Regulations (29 CFR) Part 1910.1200 (OSHA’s Hazard Communication Standard). OSHA’s Hazard Communication Standard and the currently referenced edition of GHS shall be used in conjunction with this publication when classifying products and creating labels.

This publication is not intended to address state, provincial, territorial, or local regulatory label and marking requirements, such as the “Proposition 65” warnings required by the state of California. It also does not fully address the requirements of the Canadian Hazardous Product Regulations-Workplace Hazardous Materials Information System 2015 (WHMIS 2015), which has adopted the 5th revised edition of GHS. The example labels provided in this guideline for Canadian transport comply with WHMIS 2015.

CGA C-7: What’s Included

This safety standard includes examples of labels, markings, decals, tags, stenciling, and similar methods of presenting precautionary information warning of principal physical and health hazards involved in the handling and use of specific products.

Labels are applied to compressed gas and cryogenic liquid containers to identify the container contents and to warn of principal physical and health hazards associated with the container and its contents. Containers in transportation not exceeding 454 kg (1000 lb) water capacity require the U.S. Department of Transportation (DOT) and Transport Canada (TC) hazard label.

Labels provided within CGA C-7 that are formatted to provide cylinder handling and storage information may be modified in order to be applied to fixed storage vessels, portable tanks, tube trailers, cargo tanks, or other packaging.

Appendix A illustrates the basic marking consisting of DOT or TC proper shipping name; identification number; and 30-mm (1.25-in) diamond, which is permitted under conditions authorized by DOT and TC regulations as an alternative to the DOT/TC 100-mm (3.9-in) diamond label and marking.

Appendices B, C, and portions of F provide additional labeling and marking information to aid in complying with applicable regulations of the U.S. Food and Drug Administration (FDA) for the labeling of medical gases, including mixtures, that are classified as drugs and medical devices.

Appendix D includes the GHS classifications and codes for corresponding hazard and precautionary statements, signal word, and GHS pictograms for the pure gases listed in this publication. This Appendix also contains DOT’s transportation classifications and CGA-developed hazard and precautionary statements.

Appendix E provides a decision tree to determine the classification of gaseous mixtures in accordance with OSHA’s Hazard Communication Standard.

CGA has developed additional hazard and precautionary statements to convey further information specific to the industrial and medical compressed gas industry. These additional CGA hazard and precautionary statements are included on the label examples as applicable and can be found in Appendices G and H. The rules for the use of CGA hazard and precautionary statements on labels also appear in Appendix H.

Appendix G lists the codes and the preferred wording for the corresponding GHS/OSHA/CGA hazard and precautionary statements to convey further information specific to hazards in the compressed gas industry. Rules for their use on labels also appear in this appendix.

Safety Responsibilities

It is the responsibility of the gas supplier to ensure that labels adequately warn of physical, health, and environmental hazards, provide appropriate precautionary measures, and comply with applicable governmental regulations. These regulations include the requirements of DOT, U.S. Environmental Protection Agency (EPA), FDA, OSHA, and, in Canada, TC and Health Products and Food Branch Inspectorate (HPFBI).

Those handling and using compressed gas containers have a responsibility to read and follow the recommendations from the precautionary information on labels, markings, and safety data sheets (SDSs). It is also important that users obtain the necessary knowledge and expertise to safely use the gas, container, and related apparatus.

The most important information on any gas container label or marking is the name of the product in the container. Every user must check the name of the product on the container label or marking before use to be sure that the product is suitable for the particular application. This product identification should bring to the user’s mind the product’s physical and health hazards and safety precautions. These precautions should be followed to handle and use the product safely.