Caustic soda, also referred to as sodium hydroxide, is a white odorless solid that is highly corrosive. It is used in the production of various chemicals, as well as in petroleum refining and paper production. It is extremely hazardous to the eyes and can lead to permanent damage and blindness. Contact with skin can cause irritation and burns. Inhalation can inflame the lungs and cause coughing, shortness of breath, and fluid accumulation.
Chlorine is a greenish-yellow gas with a strong irritating odor.
It is produced electrolytically from a salt solution. Chlorine gas is also used as bleach in the production of paper and for disinfecting drinking water. Chlorine gas was used as a chemical weapon in the First World War and exposure can be rapidly fatal. There have been numerous releases of chlorine from industrial facilities, many of them resulting in deaths. Long-term exposure to lower levels of chlorine is reported to cause respiratory complaints and corrosion of the teeth.