Chemical safety

Chemical safety involves all the policies and practices used to lower the risk of exposure to hazardous substances. These substances can be dangerous to the people handling them, the surrounding environment, and entire ecosystems. Chemicals exist in many forms, such as pure substances, mixtures, solutions, or emulsions. They are found everywhere in modern life, from large industrial plants to private homes. Maintaining safety is vital because certain chemicals can produce toxic or explosive byproducts if they mix incorrectly.

Chemical safety is distinct from a field called process safety. Process safety focuses specifically on industrial plants and major accidents involving substances like hydrocarbons. Chemical safety, however, looks at both immediate and long-term effects, such as carcinogenicity, which is the ability to cause cancer. The dangers are high; it is estimated that 1.6 million human deaths occur annually from contact with hazardous chemicals. In 2016, the world lost 45 million disability-adjusted life-years due to these risks, a significant increase from 2012.

Chemicals possess various properties that make them hazardous to life. Some are flammable, meaning they catch fire easily, while others are explosive. Corrosive substances, such as strong acids or alkalis, can cause chemical burns on contact. Toxic materials can exist as solids, liquids, or gases. These can enter the body through inhalation, skin contact, or by touching mucous membranes in the eyes and nose. Some chemicals, like mercury, arsenic, or dioxins, are persistent. This means they can stay in the body for long periods, often by being stored in fat cells.

Environmental risks can be difficult to see right away. For example, the release of CFCs threatened the Earth's ozone layer, requiring global scientific investigation. Scientists are also studying how persistent halogenated organics affect marine food chains. These chemicals can become concentrated in the fatty deposits of top predators, which may impact their reproductive success. Managing these risks requires strict laws. In the European Union, the European Chemicals Agency manages the REACH system to ensure compliance. In the United States, the U.S. Chemical Safety and Hazard Investigation Board investigates major accidents to recommend ways to prevent them.

Different regions use different legal frameworks to enforce safety. The United Kingdom uses the Health and Safety at Work etc. Act 1974 to cover workplace safety. The Health and Safety Executive (HSE) investigates major incidents and provides safety guidance there. New Zealand uses the Health and Safety at Work (Hazardous Substances) Regulations 2017, which are enforced by an agency called Worksafe. However, New Zealand's rules do not extend to domestic or educational settings. In the US, control is divided between state and federal government levels.

Accidents often occur during the manufacturing process. Creating one chemical can sometimes produce a dangerous byproduct. For instance, making the herbicide 2,4,5-Trichlorophenol requires reacting chlorine with phenol. This process can create 2,3,7,8-tetrachlorodibenzodioxin, a highly toxic dioxin. The use of this chemical once led to the abandonment of Times Beach, Missouri. Another famous event was the Bhopal disaster, where the poisonous gas methyl isocyanate was released.

Even at home, chemicals like bleach or caustic soda pose risks. Modern cleaning "pods" can also increase the risk of misuse by small children.

To manage these risks, workers use Personal Protective Equipment, or PPE. This includes safety goggles to protect the eyes, as well as gloves, lab coats, and closed-toed shoes. While PPE helps minimize exposure, it is not a complete solution on its own. Labels also play a major role in safety. Many countries use the Globally Harmonized System of pictograms to show hazards. In the U.S., the NFPA diamond is used to identify risks through four colors. Red indicates flammability, blue shows health hazards, yellow shows reactivity, and white shows special hazards. Numbers from 0 to 4 on these labels indicate the level of danger, with 4 being extremely hazardous. Finally, manufacturers provide Safety Data Sheets (SDSs) to give detailed information about workplace health and emergency procedures.