L'Air Liquide is engaged in the market of gases for industry, health and the environment. Oxygen, nitrogen, hydrogen, and rare gases make up Co.'s core activities. Co. structures its activities in three segments: Gas and Services, Engineering and Technology, and Other activities. The Gas and Services segment comprises four business lines: Industrial Merchant, Large Industries, Healthcare and Electronics; Engineering and Technology designs, develops and builds industrial gas production plants for Co. and third parties; and the Other Activities segment develops welding and cutting edge technologies, and markets deep-sea diving and swimming equipment to professionals and privates individuals.