Substitution of less hazardous

Substitution means the replacement of a hazardous material or process with an alternative which reduces or eliminates the hazard. Process designers, line managers, and plant technical staff should continually ask if less hazardous alternatives can be effectively substituted for all hazardous materials used in a manufacturing process. Examples of substitution in two categories are discussed—reaction chemistry and solvent usage. There are many other areas where opportunities for substitution of less hazardous materials can be found, for example, materials of construction, heat transfer media, insulation, and shipping containers. 

A. Elimination or reduction of further exposure is a key treatment intervention in occupational toxicology. This includes prevention of exposure of coworkers. The Occupational Safety and Health Administration (OSHA) may be of assistance and should be notified immediately about an ongoing, potentially life-threatening workplace exposure situation. Contact information for region OSHA offices is listed in Table IV-3. Workplace modification and control, especially the substitution of less hazardous materials, should always be the first line of defense. Worker-required personal protective equipment is, in general, less preferred. 

B. Substitution of less hazardous materials, processes, operations, or equipment... 

B. Substitution of Less Hazardous Materials, Processes, Operations, or Equipment Processes... 

In this report, this term also includes attempts to reduce or eliminate the use in commerce of chemicals associated with health or environmental risks. Examples include the phase-out of lead in gasoline, the attempt to phase out the use of asbestos, and efforts eliminate emissions of chlorofiuorocarbons and halons. Some of these attempts have involved substitution of less hazardous chemicals for compariable uses, but other involve the elimination of a particular process or product from the market without direct substitution. 

A number of less-hazardous reagents that can be substituted for tert-hutyl azidoformate in tert-butoxycarbonylation reactions are available including 2-(te/t-butoxycarbonyloxyimino)-2-phenylacetonitrile (Aldrich Chemical Company), 0-teri-hutyl N-phenyl thiocarbonate (Eastman Organic Chemicals), di-butyl dicarbonate and tert-butyl phenyl carbonate. ... 

While minimization possibilities are being investigated, substitutions should also be considered as an alternative or companion concept that is, safer materials should be used in place of hazardous ones. This can be accomplished by using alternative chemistry that allows the use of less hazardous materials or less severe processing conditions. When possible, toxic or flammable solvents should be replaced with less hazardous solvents (for example, water-based paints and adhesives and aqueous or dry flowable formulations for agricultural chemicals). 

The Principle of Substitution states that hazardous chemicals should be systematically substituted by less hazardous alternatives or preferably alternatives for which no hazards can be identified. 

The aim was to assess the feasibility of substitution with less hazardous flame retardants. They selected red phosphorus, ammonium polyphosphate and aluminium trihydroxide as the least environmentally problematic alternatives. Red phosphorus can technically be used in a variety of polymers to meet even the toughest fire safety standards, although it may network forall applications. ... 

The drawing up of programmes and measures by 2003 for the control of discharges, emissions and losses of substances on [the Priority] list, and their substitution with less hazardous or non-hazardous substances where feasible ... 

The Substitution Principle is closely tied to the general goal of elimination, which is manifested in Article 5. A direct consequence of the employment of the Substitution Principle is the application of best Available Technologies (BAT) and Best Environmental Practice (BEP) when dealing with unintentional sources as classified in Annex C. BAT as such also requires the use of less hazardous substances. (Annex C, part V, (A (b)) again refers to the Substitution Principle demanding in para (d) the replacement of feed materials which are POPs or where there is a direct link between the materials and releases of POPs from the source and consequently health effects and harm for humans and the environment. 

Substitution generally means that one substance or process is substituted for another, for whatever reason (availability, costs, technical requirements). Substitution of a hazardous substance or product signifies its replacement by less a hazardous substance, product or process. In this context the scope ranges from simple substitution (i.e. exchanging substances) to risk management as a whole (i.e. prevention of hazardous substances, reduction or prevention of exposure, etc.). 

Risk management The substitution of a hazardous substance contained in a product or a process by a less hazardous substance may be an appropriate way of reducing risks. Modified technical systems or methods can, however, also be considered as additional or complementaiy in action. Management systems for developing less hazardous substances and for the secure use of hazardous substances (closed systems, certification of users) are also part of this process. We... 

Secure chemistry— to minimize the misuse of chemicals and chemical assets as weapons of destruction. Challenges for chemical scientists include the substitution of less toxic chemicals in the manufacturing process and the minimization of the accumulation and storage of hazardous intermediates and products. 

Compared to conventional methods, the microwave-assisted approach has a major advantage in requiring a very short reaction time. The method is technically simple and allows for the use of less hazardous reagents (e.g., KOH substituting the conventionally used NaOEt). Still, the reaction lacks from a drawback of being performed in a two-step sequence, with necessary isolation of the intermediate hydrazone. 

It may be possible to substitute a less hazardous material for a hazardous product. For example, bleaching powder can be used in swimming pools instead of chlorine.4 Benzoyl peroxide, an initiator used in polymerization reactions, is available as a paste in water, which makes it much less shock-sensitive than the dry form. Other substitutions that have been used to make transportation, storage, and processing safer include ... 

Retailers - General bans and restrictions in relation to supply and use - Substitution with less hazardous chemicals - Licenses imp/exp/ trade - Authorization (pesticides, biocides, others) - Registration of chemicals... 

The QSAR-partial order ranking system further appears as an appropriate tool to give specific molecules an identity in relation to others and thus constitute as a support tool in the development of less hazardous substitutes to acknowledged harmful substances. In this connection partial order ranking potentially also constitute a rather strong tool to solve inverse QSAR problems, e.g., to develop suitable synthetic pathways for new substances. 

At the top of the hierarchy, the ideal way to deal with the hazard is to eliminate it totally or to substitute a less hazardous substance, process or piece of machinery. An example would be to use clips, clamps or bolts as joining devices instead of a toxic adhesive. 

A emunon mistake wben substimting materials is to replace a chemical of known toxicity with one t ch has not been adequately or completely evaluated for toxicity, under the assumption diat lack of information implies that a chemical is s. The identification of less hazardous substitutes will depend on having adequate and current data and to-... 

In the case of substances identified as hazardous to health, the Control of Substances Hazardous to Health Regulations 1988 (COSHH) require that exposure to them must be either prevented or controlled. Prevention of exposure can be achieved by either a prohibition on the use of the substance, total enclosure of the source or by substituting a less hazardous substance. Control, on the other hand, may entail an engineering solution, such as the installation and operation of local exhaust ventilation systems, or by changing the process to afford better operator protection. In relatively low risk situations the provision and use of specific items of personal protective equipment may afford the appropriate level of operator protection. In all cases, prevention and control strategies should be supported by the provision of information, instruction and training for staff and adequate supervision. 

Another type of control approach should always be considered when working with chemical or welding exposures—substituting a less hazardous product for a more hazardous product. MSDS on... 

So far the emphasis has been on substituting hazardous materials or using less, i.e., intensification. Let us now consider use of hazardous materials under less hazardous conditions, i.e. at less extreme temperatures or pressures or as a vapor rather than superheated liquid or diluted, in other words, attenuation. ... 

---