Hazard substitution

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Hazard substitution is a hazard control strategy in which a material or process is replaced with another that is less hazardous. Substitution is the second most effective of the five members of the hierarchy of hazard controls in protecting workers, after elimination. [1] [2] [3] Substitution and elimination are most effective early in the design process, when they may be inexpensive and simple to implement, while for an existing process they may require major changes in equipment and procedures. [1] The concept of prevention through design emphasizes integrating the more effective control methods such as elimination and substitution early in the design phase. [4]

Contents

Hazard substitutions can involve not only changing one chemical for another, but also using the same chemical in a less hazardous form. Substitutions can also be made to processes and equipment. In making a substitution, the hazards of the new material should be considered and monitored, so that a new hazard is not unwittingly introduced, [3] causing "regrettable substitutions". [5] Substitution can also fail as a strategy if the hazardous process or material is reintroduced at a later stage in the design or production phases, [6] or if cost or quality concerns cause a substitution to not be adopted. [7]

Examples

Chemicals

A common substitution is to replace a toxic chemical with a less toxic one. [8] Some examples include replacing the solvent benzene, a carcinogen, with toluene; switching from organic solvents to water-based detergents; and replacing paints containing lead with those containing non-leaded pigments. [3] Dry cleaning can avoid the use of toxic perchloroethylene by using petroleum-based solvents, supercritical carbon dioxide, or wet cleaning techniques. [9] Chemical substitutions are an example of green chemistry. [5]

Chemicals can also be substituted with a different form of the same chemical. In general, inhalation exposure to dusty powders can be reduced by using a slurry or suspension of particles in a liquid solvent instead of a dry powder, [10] or substituting larger particles such as pellets or ingots. [3] Some chemicals, such as nanomaterials, often cannot be eliminated or substituted with conventional materials because their unique properties are necessary to the desired product or process. [10] However, it may be possible to choose properties of the nanoparticle such as size, shape, functionalization, surface charge, solubility, agglomeration, and aggregation state to improve their toxicological properties while retaining the desired functionality. [11]

In 2014, the U.S. National Academies released a recommended decision-making framework for chemical substitutions. The framework maintained health-related metrics used by previous frameworks, including carcinogenicity, mutagenicity, reproductive and developmental toxicity, endocrine disruption, acute and chronic toxicity, dermal and eye irritation, and dermal and respiratory sensitization, and ecotoxicity. It added an emphasis on assessing actual exposure rather than only the inherent hazards of the chemical itself, decision rules for resolving trade-offs among hazards, and consideration of novel data sources on hazards such as simulations. The assessment framework has 13 steps, many of which are unique, such as dedicated steps for scoping and problem formulation, assessing physicochemical properties, broader life-cycle assessment, and research and innovation. The framework also provides guidance on tools and sources for scientific information. [12]

Processes and equipment

An aerosol droplet containing nanomaterials ejected from a vial during sonication. Eliminating or limiting sonication and other handling processes reduces inhalation hazards. Nanomaterials aerosol.png
An aerosol droplet containing nanomaterials ejected from a vial during sonication. Eliminating or limiting sonication and other handling processes reduces inhalation hazards.

Hazards to workers can be reduced by limiting or replacing procedures that may aerosolize toxic materials contained in the item. Examples include limiting agitation procedures such as sonication, or by using a lower-temperature process in chemical reactors to minimize release of materials in exhaust. [13] Substituting a water-jet cutting process instead of mechanical sawing of a solid item also creates less dust. [14]

Equipment can also be substituted, for example using a self-retracting lifeline instead of a fixed rope for fall protection, [15] or packaging materials in smaller containers to prevent lifting injuries. [16] Health effects from noise can be controlled by purchasing or renting less noisy equipment. This topic has been the subject of several Buy Quiet campaigns, and the NIOSH Power Tools Database contains data on sound power, pressure, and vibration levels of many power tools. [17] [18]

Regrettable substitutions

The synthesis of N-vinyl formamide requires use of the highly toxic hydrogen cyanide (H-CN). Even though the end product is a less-toxic alternative to acrylamide for end users, the hazards to workers manufacturing the material should also be considered in an alternatives assessment. VFA Synthesis 01.png
The synthesis of N-vinyl formamide requires use of the highly toxic hydrogen cyanide (H-CN). Even though the end product is a less-toxic alternative to acrylamide for end users, the hazards to workers manufacturing the material should also be considered in an alternatives assessment.

A regrettable substitution occurs when a material or process believed to be less hazardous turns out to have an unexpected hazard. One well-known example occurred when dichloromethane was phased out as a brake cleaner due to its environmental effects, but its replacement n-hexane was subsequently found to be neurotoxic. [5] [12] Often the substances being replaced have well-studied hazards, but the alternatives may have little or no toxicity data, making alternatives assessments difficult. [5] Often, chemicals with no toxicity data are considered preferable since they do not prompt such concerns as a California Proposition 65 warning. [19]

Another type of regrettable substitution involves shifting the burden of a hazard to another party. One example is that the potent neurotoxin acrylamide can be replaced with the safer N-vinyl formamide, but the synthesis of the latter requires use of the highly toxic hydrogen cyanide, increasing the hazards to workers in the manufacturing firm. In performing an alternatives assessment, including the effects over the entire product lifecycle as part of a life-cycle assessment can mitigate this. [12]

Related Research Articles

<span class="mw-page-title-main">Occupational hygiene</span> Management of workplace health hazards

Occupational hygiene is the anticipation, recognition, evaluation, control, and confirmation (ARECC) of protection from risks associated with exposures to hazards in, or arising from, the workplace that may result in injury, illness, impairment, or affect the well-being of workers and members of the community. These hazards or stressors are typically divided into the categories biological, chemical, physical, ergonomic and psychosocial. The risk of a health effect from a given stressor is a function of the hazard multiplied by the exposure to the individual or group. For chemicals, the hazard can be understood by the dose response profile most often based on toxicological studies or models. Occupational hygienists work closely with toxicologists for understanding chemical hazards, physicists for physical hazards, and physicians and microbiologists for biological hazards. Environmental and occupational hygienists are considered experts in exposure science and exposure risk management. Depending on an individual's type of job, a hygienist will apply their exposure science expertise for the protection of workers, consumers and/or communities.

<span class="mw-page-title-main">Nanomaterials</span> Materials whose granular size lies between 1 to 100 nm

Nanomaterials describe, in principle, materials of which a single unit is sized between 1 and 100 nm.

Nanotoxicology is the study of the toxicity of nanomaterials. Because of quantum size effects and large surface area to volume ratio, nanomaterials have unique properties compared with their larger counterparts that affect their toxicity. Of the possible hazards, inhalation exposure appears to present the most concern, with animal studies showing pulmonary effects such as inflammation, fibrosis, and carcinogenicity for some nanomaterials. Skin contact and ingestion exposure are also a concern.

An occupational exposure limit is an upper limit on the acceptable concentration of a hazardous substance in workplace air for a particular material or class of materials. It is typically set by competent national authorities and enforced by legislation to protect occupational safety and health. It is an important tool in risk assessment and in the management of activities involving handling of dangerous substances. There are many dangerous substances for which there are no formal occupational exposure limits. In these cases, hazard banding or control banding strategies can be used to ensure safe handling.

Workplace health surveillance or occupational health surveillance (U.S.) is the ongoing systematic collection, analysis, and dissemination of exposure and health data on groups of workers. The Joint ILO/WHO Committee on Occupational Health at its 12th Session in 1995 defined an occupational health surveillance system as "a system which includes a functional capacity for data collection, analysis and dissemination linked to occupational health programmes".

Prevention through design (PtD), also called safety by design usually in Europe, is the concept of applying methods to minimize occupational hazards early in the design process, with an emphasis on optimizing employee health and safety throughout the life cycle of materials and processes. It is a concept and movement that encourages construction or product designers to "design out" health and safety risks during design development. The concept supports the view that along with quality, programme and cost; safety is determined during the design stage. It increases the cost-effectiveness of enhancements to occupational safety and health.

The substitution of dangerous chemicals in the workplace is the process of replacing chemicals with less hazardous alternatives or eliminating them, generally to improve occupational health and safety or minimize harmful environmental impact. The process can be lengthy, as an assessment of dangers, costs, and practicality is necessary. Substituting hazardous chemicals follows the principles of green chemistry and results in clean technology.

<span class="mw-page-title-main">Hierarchy of hazard controls</span> System used in industry to eliminate or minimize exposure to hazards

Hierarchy of hazard control is a system used in industry to minimize or eliminate exposure to hazards. It is a widely accepted system promoted by numerous safety organizations. This concept is taught to managers in industry, to be promoted as standard practice in the workplace. It has also been used to inform public policy, in fields such as road safety. Various illustrations are used to depict this system, most commonly a triangle.

Engineering controls are strategies designed to protect workers from hazardous conditions by placing a barrier between the worker and the hazard or by removing a hazardous substance through air ventilation. Engineering controls involve a physical change to the workplace itself, rather than relying on workers' behavior or requiring workers to wear protective clothing.

Alternatives assessment or alternatives analysis is a problem-solving approach used in environmental design, technology, and policy. It aims to minimize environmental harm by comparing multiple potential solutions in the context of a specific problem, design goal, or policy objective. It is intended to inform decision-making in situations with many possible courses of action, a wide range of variables to consider, and significant degrees of uncertainty. Alternatives assessment was originally developed as a robust way to guide precautionary action and avoid paralysis by analysis; authors such as O'Brien have presented alternatives assessment as an approach that is complementary to risk assessment, the dominant decision-making approach in environmental policy. Likewise, Ashford has described the similar concept of technology options analysis as a way to generate innovative solutions to the problems of industrial pollution more effectively than through risk-based regulation.

<span class="mw-page-title-main">Occupational dust exposure</span>

Occupational dust exposure can occur in various settings, including agriculture, forestry, and mining. Dust hazards include those that arise from handling grain and cotton, as well as from mining coal. Wood dust, commonly referred to as "sawdust", is another occupational dust hazard that can pose a risk to workers' health.

The health and safety hazards of nanomaterials include the potential toxicity of various types of nanomaterials, as well as fire and dust explosion hazards. Because nanotechnology is a recent development, the health and safety effects of exposures to nanomaterials, and what levels of exposure may be acceptable, are subjects of ongoing research. Of the possible hazards, inhalation exposure appears to present the most concern, with animal studies showing pulmonary effects such as inflammation, fibrosis, and carcinogenicity for some nanomaterials. Skin contact and ingestion exposure, and dust explosion hazards, are also a concern.

Hazard elimination is a hazard control strategy based on completely removing a material or process causing a hazard. Elimination is the most effective of the five members of the hierarchy of hazard controls in protecting workers, and where possible should be implemented before all other control methods. Many jurisdictions require that an employer eliminate hazards if it is possible, before considering other types of hazard control.

<span class="mw-page-title-main">Occupational exposure banding</span> Process to assign chemicals into categories corresponding to permissible exposure concentrations

Occupational exposure banding, also known as hazard banding, is a process intended to quickly and accurately assign chemicals into specific categories (bands), each corresponding to a range of exposure concentrations designed to protect worker health. These bands are assigned based on a chemical’s toxicological potency and the adverse health effects associated with exposure to the chemical. The output of this process is an occupational exposure band (OEB). Occupational exposure banding has been used by the pharmaceutical sector and by some major chemical companies over the past several decades to establish exposure control limits or ranges for new or existing chemicals that do not have formal OELs. Furthermore, occupational exposure banding has become an important component of the Hierarchy of Occupational Exposure Limits (OELs).

<span class="mw-page-title-main">Engineering controls for nanomaterials</span>

Engineering controls for nanomaterials are a set of hazard control methods and equipment for workers who interact with nanomaterials. Engineering controls are physical changes to the workplace that isolate workers from hazards, and are considered the most important set of methods for controlling the health and safety hazards of nanomaterials after systems and facilities have been designed.

A radioactive nanoparticle is a nanoparticle that contains radioactive materials. Radioactive nanoparticles have applications in medical diagnostics, medical imaging, toxicokinetics, and environmental health, and are being investigated for applications in nuclear nanomedicine. Radioactive nanoparticles present special challenges in operational health physics and internal dosimetry that are not present for other substances, although existing radiation protection measures and hazard controls for nanoparticles generally apply.

<span class="mw-page-title-main">Characterization of nanoparticles</span> Measurement of physical and chemical properties of nanoparticles

The characterization of nanoparticles is a branch of nanometrology that deals with the characterization, or measurement, of the physical and chemical properties of nanoparticles. Nanoparticles measure less than 100 nanometers in at least one of their external dimensions, and are often engineered for their unique properties. Nanoparticles are unlike conventional chemicals in that their chemical composition and concentration are not sufficient metrics for a complete description, because they vary in other physical properties such as size, shape, surface properties, crystallinity, and dispersion state.

<span class="mw-page-title-main">Titanium dioxide nanoparticle</span>

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Anticipate, recognize, evaluate, control, and confirm (ARECC) is a decision-making framework and process used in the field of industrial hygiene (IH) to anticipate and recognize hazards, evaluate exposures, and control and confirm protection from risks. ARECC supports hazard-informed exposure assessment, exposure-informed hazard assessment, and risk-informed decision making in any endeavor.

Research on the health and safety hazards of 3D printing is new and in development due to the recent proliferation of 3D printing devices. In 2017, the European Agency for Safety and Health at Work has published a discussion paper on the processes and materials involved in 3D printing, potential implications of this technology for occupational safety and health and avenues for controlling potential hazards.

References

  1. 1 2 "Hierarchy of Controls". U.S. National Institute for Occupational Safety and Health . 2016-07-18. Retrieved 2017-03-21.
  2. ↑ "Hierarchy of Hazard Controls". New York Committee for Occupational Safety & Health. Archived from the original on 2012-03-05. Retrieved 2017-03-21.
  3. 1 2 3 4 "Hazard Control". Canadian Centre for Occupational Health and Safety . 2006-04-20. Retrieved 2017-03-21.
  4. ↑ "Prevention through Design". U.S. National Institute for Occupational Safety and Health. 2016-07-29. Retrieved 2017-03-09.
  5. 1 2 3 4 Hogue, Cheryl. "Assessing Alternatives To Toxic Chemicals". Chemical & Engineering News. Retrieved 2017-03-21.
  6. ↑ Nix, Doug (2011-02-28). "Understanding the Hierarchy of Controls". Machinery Safety 101. Retrieved 2017-03-10.
  7. ↑ Braun, John. "The Hierarchy of Controls, Part One: Elimination and Substitution". Simplified Safety Fall Protection Blog. Retrieved 2017-03-10.
  8. ↑ "Substitution of Chemicals: Considerations for Selection". Canadian Centre for Occupational Health and Safety. Retrieved 2017-03-21.
  9. ↑ "Control of Exposure to Perchloroethylene in Commercial Drycleaning (Substitution)". U.S. National Institute for Occupational Safety and Health. 1997. doi: 10.26616/NIOSHPUB97155 . Retrieved 2017-03-27.
  10. 1 2 "Current Strategies for Engineering Controls in Nanomaterial Production and Downstream Handling Processes". U.S. National Institute for Occupational Safety and Health: 9–20, 28. November 2013. doi: 10.26616/NIOSHPUB2014102 . Retrieved 2017-03-05.
  11. ↑ "Building a Safety Program to Protect the Nanotechnology Workforce: A Guide for Small to Medium-Sized Enterprises". U.S. National Institute for Occupational Safety and Health: 6–14. March 2016. doi: 10.26616/NIOSHPUB2016102 . Retrieved 2017-03-05.
  12. 1 2 3 Committee on the Design Evaluation of Safer Chemical Substitutions: A Framework to Inform Government Industry Decision; Board on Chemical Sciences Technology; Board on Environmental Studies Toxicology; Division on Earth Life Studies; National Research Council (2014-10-10). A Framework to Guide Selection of Chemical Alternatives. U.S. National Research Council. pp. 1–4, 10, 140. doi:10.17226/18872. ISBN   9780309310130. PMID   25473704.
  13. ↑ "General Safe Practices for Working with Engineered Nanomaterials in Research Laboratories". U.S. National Institute for Occupational Safety and Health: 10–28. May 2012. doi: 10.26616/NIOSHPUB2012147 . Retrieved 2017-03-05.
  14. ↑ Nix, Doug (2011-02-28). "Understanding the Hierarchy of Controls". Machinery Safety 101. Retrieved 2017-03-10.
  15. ↑ Mlynek, Joe. "Hierarchy of Controls Prioritizes Action on Workplace Hazards". Progressive Safety Services. Retrieved 2017-03-10.
  16. ↑ "Hierarchy of Controls". SA Unions . Archived from the original on 2005-06-23. Retrieved 2017-03-14.
  17. ↑ "Engineering Noise Control". U.S. National Institute for Occupational Safety and Health. 2016-12-02. Retrieved 2017-03-27.
  18. ↑ "Buy Quiet". U.S. National Institute for Occupational Safety and Health. 2016-12-13. Retrieved 2017-03-27.
  19. ↑ Maertens, Alexandra; Golden, Emily; Hartung, Thomas (2021). "Avoiding Regrettable Substitutions: Green Toxicology for Sustainable Chemistry". ACS Sustainable Chemistry & Engineering. 9 (23): 7749–7758. doi:10.1021/acssuschemeng.0c09435. PMC   9432817 . PMID   36051558. S2CID   236312765.
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