L'Air Liquide S.A. (Air Liquide) is a major French company supplying industrial gases and services to various industries including medical, chemical and electronic manufacturers. Founded in 1902 it is second on the world market in its field, operating in over 70 countries. It is headquartered in Paris, France. Air Liquide owned the patent for Aqua-Lung until it time-expired.

Although Air Liquide's headquarters is located in Paris, France, it also has a major site in Japan (ALL), as well as in Houston, TX, and Newark, DE, USA. There is an emphasis on Research and Development (R&D;) throughout the entire Air Liquide company. R&D; targets the creation of not only industrial gases, but also gases that are used in products such as healthcare items, electronic chips, foods and chemicals. The major R&D; groups within Air Liquide focus on analysis, bioresources (foods and chemicals), combustion, membranes, modeling, and the production of Hydrogen (H2) gas."