Substitution of dangerous chemicals
The substitution of dangerous chemicals in the workplace is the process of replacing chemicals with less hazardous alternatives or using no chemicals, improving occupational health and safety and minimizing harmful environmental impact. Ideally, the substitution should result in the greatest improvement possible. It can be difficult to know the long term carcinogenic, reprotoxic, allergenic, or neurotoxic effects of a substitution. The cost and practicality of the substitute are also considered because successful substitution may require technical and organizational changes. The result of a substitution may not be completely harmless, but should reduce hazards. Substituting hazardous chemicals  follows the principles of green chemistry and results in clean technology. Chemical Alternative Assessments. Alternatives assessments are used to determine which chemical is fit to be a substitute. A process-based method of substituting chemicals in the workplace involves: After listing the chemicals, their potential hazards are listed in data sheets. A process analysis is performed, which studies how and when the chemical is used and what technology, equipment, and chemistry is needed. The data sheets gives knowledge of short and long term effects of a chemical: If a risk is not "small", then possible substitutions are considered. A chemical  has a "small" risk to humans if there are no long-term negative effects, the exposure is lower than the threshold limit value (TLV), and there is no risks of disease or other health issues. Several factors must be assessed to determine if a chemical is a suitable substitute including potential hazards, exposure, technical feasibility and economical considerations. After substitutes are proposed, the risks of each substitute are compared to one another and tested until a suitable substitution is found. Hazard Assessment. The potential hazards of a chemical or a substitute candidate must be assessed by noting the toxicity of  the chemical to both humans and the environment. An assessment of the chemical should list the dangerous properties of the chemical, such as flammability or corrosivity. It should also note any carcinogenic, reprotoxic, allergenic, neurotoxic, and other related effects the chemical has on human health. Exposure Characterization. If a potential chemical substitute has greater exposure to humans and the environment than the original chemical, the toxicity of increased exposure must be considered. A chemical substitute with less exposure or a similar exposure but a lower toxicity is preferred. Life-Impacts Characterization. A life-cycle assessment of the chemical considers the  long term effects a chemical will have on human health and the environment, as well as ethical and social effects of chemical use. Examples include the addition of greenhouse gas emissions from a use of a chemical, or carcinogenic effects of a chemical after prolonged usage. An ethical or social effect considered during this assessment could include a consideration of if the chemical is ethically sourced or if its use infringes on the rights of indigenous people. Technical Feasibility. A chemical substitute ideally should perform the intended task efficiently. Sometimes the process used must be changed to substitute out a  dangerous chemical. Economic Feasibility. The availability of the chemical commercially in the quantities required is noted. A substitution that is more cost efficient is ideal, but not always possible. Legislature. Enacted in the EU in 2006, REACH requires industries to collect safety information on their chemicals and report them to a database. It also requires the substitution of dangerous chemicals to safer alternatives if they are found. The EPA uses the Toxic Substances Control Act (TSCA) to require industries with record and report the production, use, and disposal of specific dangerous chemicals. Examples. Substitution of hazardous chemicals can be on  different levels such as using