Workplaces in which chemicals are used, should assess and be prepared for the risk of accidents due to the use of chemicals. The most common chemicals causing a risk of poisoning include various acids and bases, gases and vapors irritating the airways as well as systemically toxic gases and vapors such as carbon monoxide, hydrogen cyanide and hydrogen sulfide. Antidotes that can be given to the victim of poisoning at the workplace are available for a very limited number of industrial chemicals. First aid and treatment are therefore often symptomatic.