Occupational exposure limit

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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. [1] 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.

Contents

Background

Simple representation of exposure risk assessment and management hierarchy based on available information Hierarchies of Exposure Assessment and Management.JPG
Simple representation of exposure risk assessment and management hierarchy based on available information

Occupational Exposure Limits (OELs) have been established for airborne workplace chemicals by multiple regulatory and authoritative organizations around the world for well over 60 years now. With the changing regulatory arena, shifting centers of manufacturing growth, and the move towards a more global view on occupational hygiene issues, it is important for the Occupational Hygiene profession to understand the current and growing issues impacting the continued viability of OEL's in our professional practice. [2]

Although peer-reviewed health-based OELs are preferred for establishing safe levels of exposure or for implementing adequate controls to provide worker protection, the lack of publicly available OELs have led to other sources of safe levels to protect workers. Industrial or Occupational Hygienists are often on the front line of anticipating and recognizing the hazards of chemical exposure for workers, and must assess the risk of exposure through the use of OELs so that proper control strategies can be implemented to keep workers below the OEL values. In the absence of OELs however, there are a variety of tools that can and should be used to assess exposure potential of workers. The "Hierarchy of OELs" provides a continuum of occupational exposure limit values that allow assessment of the risk of exposure in order to apply adequate controls. [3]

Hierarchy of occupational exposure limits (OELs) Hierarchy of Occupational Exposure Limits.JPG
Hierarchy of occupational exposure limits (OELs)
Illustration of statistical output from IHSTAT using air sampling data Analysis of air sampling data using IHSTAT.JPG
Illustration of statistical output from IHSTAT using air sampling data

Personal air sampling is routinely conducted on workers to determine whether exposures are acceptable or unacceptable. These samples are collected and analyzed using validated sampling and analytical methods. These methods are available from OSHA Technical Manual and NIOSH Manual of Analytical Methods [4] Statistical tools are available to assess exposure monitoring data against OELs. The statistical tools are typically free but do require some previous knowledge with statistical concepts. A popular exposure data statistical tool called "IH STAT" is available from AIHA (American Industrial Hygiene Association). IHSTAT has 14 languages including English and is available for free. [5]

Methods for performing occupational exposure assessments can be found in "A Strategy for Assessing and Managing Occupational Exposures, Third Edition Edited by Joselito S. Ignacio and William H. Bullock". [6]

With the World Health Organization and the International Labour Office having now quantified the global burden of disease from psychosocial occupational hazards, [7] identification of OELs for such hazards is increasingly becoming a focus of attention for occupational safety and health policy and practice.

Types

International limit values

The database ″GESTIS - International limit values for chemical agents″ [8] contains a collection of occupational limit values for hazardous substances collected from over 30 countries: various EU member states, Australia, Canada, Israel, Japan, New Zealand, Singapore, South Korea, Switzerland, China, Turkey, and the United States. The database comprises values of more than 2,000 substances.

The present database was elaborated in co-operation with experts from various international occupational safety and health institutions. It aims to give an overview of limit values in different countries. Since the limit values vary in their handling, the level of protection, and their legal relevance, the original lists of limit values and the explanations there should be considered as primary sources. Also the chemical nomenclature is diverging, synonyms can for example be found in the GESTIS Substance Database.

The database is also available as an app for mobile terminals with Android or iOS operating systems.

See also

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The American Conference of Governmental Industrial Hygienists (ACGIH) is a professional association of industrial hygienists and practitioners of related professions, with headquarters in Cincinnati, Ohio. One of its goals is to advance worker protection by providing timely, objective, scientific information to occupational and environmental health professionals.

Occupational hygiene Management of workplace health hazards

Occupational hygiene is the anticipation, recognition, evaluation, control, and confirmation of protection from hazards at work that may result in injury, illness, or affect the well being of workers. 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.

Chemical hazard Non-biological substance that has the potential to cause harm to life or health

A chemical hazard is a (non-biological) substance that has the potential to cause harm to life or health. Chemicals are widely used in the home and in many other places. Exposure to chemicals can cause acute or long-term detrimental health effects. There are many types of hazardous chemicals, including neurotoxins, immune agents, dermatologic agents, carcinogens, reproductive toxins, systemic toxins, asthmagens, pneumoconiotic agents, and sensitizers. In the workplace, exposure to chemical hazards is a type of occupational hazard. The use of protective personal equipment(PPE) may substantially reduce the risk of damage from contact with hazardous materials.

The threshold limit value (TLV) is believed to be a level to which a worker can be exposed per shift in the worktime without adverse effects. Strictly speaking, TLV is a reserved term of the American Conference of Governmental Industrial Hygienists (ACGIH). TLVs issued by the ACGIH are the most widely accepted occupational exposure limits both in the United States and most other countries. However, it is sometimes loosely used to refer to other similar concepts used in occupational health and toxicology, such as acceptable daily intake (ADI) and tolerable daily intake (TDI). Concepts such as TLV, ADI, and TDI can be compared to the no-observed-adverse-effect level (NOAEL) in animal testing, but whereas a NOAEL can be established experimentally during a short period, TLV, ADI, and TDI apply to human beings over a lifetime and thus are harder to test empirically and are usually set at lower levels. TLVs, along with biological exposure indices (BEIs), are published annually by the ACGIH.


Exposure assessment is a branch of environmental science and occupational hygiene that focuses on the processes that take place at the interface between the environment containing the contaminant of interest and the organism being considered. These are the final steps in the path to release an environmental contaminant, through transport to its effect in a biological system. It tries to measure how much of a contaminant can be absorbed by an exposed target organism, in what form, at what rate and how much of the absorbed amount is actually available to produce a biological effect. Although the same general concepts apply to other organisms, the overwhelming majority of applications of exposure assessment are concerned with human health, making it an important tool in public health.

Control of Substances Hazardous to Health Regulations 2002 United Kingdom legislation

The Control of Substances Hazardous to Health Regulations 2002 is a United Kingdom Statutory Instrument which states general requirements imposed on employers to protect employees and other persons from the hazards of substances used at work by risk assessment, control of exposure, health surveillance and incident planning. There are also duties on employees to take care of their own exposure to hazardous substances and prohibitions on the import of certain substances into the European Economic Area. The regulations reenacted, with amendments, the Control of Substances Hazardous to Work Regulations 1999 and implement several European Union directives.

A recommended exposure limit (REL) is an occupational exposure limit that has been recommended by the United States National Institute for Occupational Safety and Health. The REL is a level that NIOSH believes would be protective of worker safety and health over a working lifetime if used in combination with engineering and work practice controls, exposure and medical monitoring, posting and labeling of hazards, worker training and personal protective equipment. To formulate these recommendations, NIOSH evaluates all known and available medical, biological, engineering, chemical, trade, and other information. Although not legally enforceable limits, RELS are transmitted to the Occupational Safety and Health Administration (OSHA) or the Mine Safety and Health Administration (MSHA) of the U.S. Department of Labor for use in promulgating legal standards.

Control banding is a qualitative or semi-quantitative risk assessment and management approach to promoting occupational health and safety. It is intended to minimize worker exposures to hazardous chemicals and other risk factors in the workplace and to help small businesses by providing an easy-to-understand, practical approach to controlling hazardous exposures at work.

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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”.

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Occupational safety and health Field concerned with the safety, health and welfare of people at work

Occupational safety and health (OSH), also commonly referred to as occupational health and safety (OHS), occupational health, or occupational safety, is a multidisciplinary field concerned with the safety, health, and welfare of people at occupation. These terms also refer to the goals of this field, so their use in the sense of this article was originally an abbreviation of occupational safety and health program/department etc.

Occupational toxicology is the application of toxicology to chemical hazards in the workplace. It focuses on substances and conditions that occur in workplaces, where inhalation exposure and dermal exposure are most important, there is often exposure to mixtures of chemicals whose interactions are complex, health effects are influenced or confounded by other environmental and individual factors, and there is a focus on identifying early adverse affects that are more subtle than those presented in clinical medicine.

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.

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Occupational exposure banding 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).

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.

References

  1. European Agency for Safety and Health at Work. "Occupational Exposure Limits" . Retrieved 2008-04-24.
  2. IOHA. "International OEL Issues and Activities \". Archived from the original on 2015-08-11.
  3. AIHA. "Webinar: The New Era of Global Exposure Limit Setting Processes - Harmonization on an OEL Hierarchy Approach".
  4. NIOSH Manual of Analytical Methods
  5. "Link to freeware version IHSTAT via AIHA Exposure Assessment Strategies website" https://www.aiha.org/get-involved/VolunteerGroups/Pages/Exposure-Assessment-Strategies-Committee.aspx/ Archived 2019-03-23 at the Wayback Machine
  6. "A Strategy for Assessing and Managing Occupational Exposures, Third Edition Edited by Joselito S. Ignacio and William H. Bullock AIHA Press" http://iweb.aiha.org/iweb/Purchase/ProductDetail.aspx?Product_code=AEAK06-327/%5B%5D
  7. Pega, Frank; Nafradi, Balint; Momen, Natalie; Ujita, Yuka; Streicher, Kai; Prüss-Üstün, Annette; Technical Advisory Group (2021). "Global, regional, and national burdens of ischemic heart disease and stroke attributable to exposure to long working hours for 194 countries, 2000–2016: A systematic analysis from the WHO/ILO Joint Estimates of the Work-related Burden of Disease and Injury". Environment International. 154: 106595. doi: 10.1016/j.envint.2021.106595 . PMC   8204267 . PMID   34011457.
  8. Institute for Occupational Safety and Health of the German Social Accident Insurance: GESTIS – International limit values for chemical agents (Occupational exposure limits, OELs), http://www.dguv.de/ifa/gestis/gestis-internationale-grenzwerte-fuer-chemische-substanzen-limit-values-for-chemical-agents/index-2.jsp

Bibliography