Identification of critical industry skills in an industrial hygiene graduate training program

Graduates of industrial hygiene training (IH) programs must be able to meet continuously evolving health and safety needs in a wide variety of occupational settings. Therefore, academic IH graduate programs must regularly evaluate their curricula and solicit input from industry professionals to make curricular changes that will better prepare their students for professional roles in industry. The purpose of this study was to identify the training gaps that existed between industry needs and the current curriculum for a United States-accredited IH graduate training program. The research team facilitated two group interviews with the IH program advisory board, collected alumni survey data, and performed a qualitative analysis to identify skills gaps/needs for the IH Program graduates. The research team identified 3 themes from participant interviews and alumni surveys (technical, applied, and essential skills) and selected several skills within each theme that interview participants thought were necessary proficiencies for junior IH professionals. The skills identified in the qualitative interview and survey data can be incorporated into the curriculum to improve the training of IH graduate students. Additionally, by using qualitative analysis, the researchers uncovered essential skills previously unidentified in IH needs assessments, providing valuable information for all IH graduate programs.

Visualizing the NIOSH Pocket Guide: Open-source web application for accessing and exploring the NIOSH Pocket Guide to Chemical Hazards

The NIOSH Pocket Guide to Chemical Hazards is a trusted resource that displays key information for a collection of chemicals commonly encountered in the workplace. Entries contain chemical structures-occupational exposure limit information ranging from limits based on full-shift time-weighted averages to acute limits such as short-term exposure limits and immediately dangerous to life or health values, as well as a variety of other data such as chemical-physical properties and symptoms of exposure. The NIOSH Pocket Guide (NPG) is available as a printed, hardcopy book, a PDF version, an electronic database, and a downloadable application for mobile phones. All formats of the NIOSH Pocket Guide allow users to access the data for each chemical separately, however, the guide does not support data analytics or visualization across chemicals. This project reformatted existing data in the NPG to make it searchable and compatible with exploration and analysis using a web application. The resulting application allows users to investigate the relationships between occupational exposure limits, the range and distribution of occupational exposure limits, and the specialized sorting of chemicals by health endpoint or to summarize information of particular interest. These tasks would have previously required manual extraction of the data and analysis. The usability of this application was evaluated among industrial hygienists and researchers and while the existing application seems most relevant to researchers, the open-source code and data are amenable to modification by users to increase customization.

Occupational exposure to asbestos in the steel industry (1972-2006)

BACKGROUND

Historically, the use of asbestos in steelmaking has been limited to a few applications. Due to its physical and chemical properties, asbestos was not necessary or suitable for most purposes in a steel mill. The few applications where asbestos were used (i.e., certain gaskets, brakes, protective cloth, refractory materials, insulation materials, and hot top products) were replaced by alternative materials as they became available.

OBJECTIVE

We discuss historical uses of asbestos in steel manufacturing and the associated airborne asbestos concentrations collected at sixteen U. S. Steel facilities between 1972 and 2006.

METHODS

A total of 495 personal airborne asbestos samples from the U. S. Steel industrial hygiene records were analyzed across four time periods corresponding to changes in the OSHA permissible exposure limit (PEL) for asbestos. 68% of the samples (n = 337) were considered representative of an employee's workday. The remaining samples (n = 158) represented task samples. Samples were grouped by facility, department, and job category within the four time periods.

RESULTS

The average fiber concentrations measured for each facility and department over time were below the contemporaneous OSHA PEL. The mean representative workday asbestos air concentration from 1972 and 1975 was 1.09 f/cc. The mean representative workday concentration decreased to 0.13 f/cc between 1976 and 1985, then decreased again to 0.02 f/cc between 1986 and 1993 and 0.03 f/cc between 1994 and 2006. For task samples, the mean air concentration from 1972 to 1975 was 3.29 f/cc. The mean task sample concentration decreased to 0.48 f/cc between 1976 and 1985, then decreased again to 0.01 f/cc between 1986 and 1993 and 0.03 f/cc between 1994 and 2006. Only eleven out of the 495 samples (2.2%), for both task and representative workday samples, were in exceedance of the contemporaneous PEL(as an 8-hour TWA), ten of which occurred prior to 1978. Eight of these eleven PEL exceeding samples were task samples. Of the remaining three representative workday samples, two had unknown sampling times.

IMPACT

This paper presents an analysis of all the available personal sampling data for airborne asbestos across 16 facilities of the U. S. Steel Corporation between 1972 and 2006. This dataset has previously never been publicly shared or analyzed. It represents one of the more complete industrial hygiene datasets from a corporation to be presented in a scientific journal and, due to the similarities in the processes at each mill, it should reflect analogous exposures throughout the steelmaking industry in the United States. One of the benefits of presenting these data is that it also provides insight into where asbestos-containing materials (ACMs) were used in the steel making process. This is just one example of a large firm that released information that had previously remained in file cabinets for decades. We believe that another benefit of publishing this paper is that it may encourage the largest firms in industry to assemble and analyze their industrial hygiene data to benefit the occupational hygiene, medical, and epidemiology communities. This can support future epidemiology studies and improve the design of future industrial hygiene programs.

Development of an interprofessional task-based learning program in the field of occupational health: a content validity study

OBJECTIVE

One of the duties of the educational system is to provide situations in which students learn the tasks corresponding to their future careers in an interprofessional team. This study was designed to develop an interprofessional task-based training program.

METHODS

This was a curriculum development study conducted by content validity methodology in two stages: 1) 'framework development' which resulted in the creation of the framework items; and 2) 'evaluation of the framework' (judgment and quantification). The first stage consisted of task identification, generation of sub-tasks, and assimilation of items into a usable format. The second stage consisted of the judgment -quantification of the content validity of items and the framework. After that, the framework of the tasks of the occupational health team was finalized in the expert panel. After explaining the tasks, a matrix for task-expected roles in the occupational health team and a matrix for task-required skills to perform each task were developed. The next step determined the appropriate teaching and assessment methods for each task. Finally, an expert panel reviewed and approved the components of the interprofessional task-based training program.

RESULTS

Integrating the interprofessional education strategy with task-based learning was considered innovative in occupational health team training. In the development stage, 48 items were extracted, and then 35 tasks were generated in the step of identification of tasks. In the second step, 174 sub-tasks were developed. The tasks and sub-tasks were categorized into seven areas. After the stage of evaluation of the framework, 33 tasks were categorized into seven main areas, including "assessment and identification of workplace hazards" (n = 10), "control of occupational hazards" (n = 4), "determining the appropriate job position for each person" (n = 3), "occupational health examinations" (n = 6), "management of occupational/work-related diseases" (n = 5), "inter-organizational and inter-disciplinary relations, and legal judgment" (n = 3) and "education and scholarship in occupational health services" (n = 2).

CONCLUSION

The results of the present study can be used in developing the use of the interprofessional strategy and task-based training as two appropriate strategies for the purposeful development of learners' abilities in the fields involved in providing occupational health services in their future careers.

Assessment of Workplace Hygiene among Contractual Workers in the Steel and Power Industry of Odisha, India

BACKGROUND

Workplace hygiene is vital in controlling infectious diseases in industries. The factors like unhealthy environment, unhygienic workplace, and contact between healthy and disease-affected employees cause industrial hazards in workplaces.

OBJECTIVES

This study assessed various components of workplace hygiene among industrial workers.

MATERIALS AND METHODS

A quantitative survey has been conducted in a steel, and power industry limited in Odisha. The study surveyed 425 male contractual workers for primary data on workplace hygiene. Probability proportion to sample technique adopted for justification of the sample. The univariate and bivariate analysis models have been done according to the study's objective.

RESULTS

Nearly 92% of respondents reported proper use of washing facilities, and 97% used toilet and urinal appropriately. One-fourth of respondents use personal disinfected clothing, and 92.2% have access to safe drinking water. The factors such as education, technical education, and occupation are significantly associated with respondents' use of washing facilities, dining hall, personal protective clothing, safe drinking water, proper cleaning, and sanitation at the workplace.

CONCLUSION

Workplace hygiene strengthens the safety measures at the workplace and reduces the incidences of occupational hazards.

Exposure assessment of nanotitanium oxide powder handling using real-time size-selective particle number concentration measurements and X-ray fluorescence spectrometry -The possibility of exposure to nonagglomerated nanomaterials during the handling of nanomaterial fine powders

In this study, airborne particles were collected using filters, and the particle number concentrations were measured in two nanotitanium dioxide (nanoTiO²)-manufacturing plants. Real-time particle size measurements were performed using both optical and scanning mobility particle sizer and X-ray fluorescence spectrometry (XRF). The respirable particles collected using filters were used to analyze Ti concentrations in the workplace air of two factories engaged in nanoTiO² powder bagging processes. The XRF analysis revealed sufficient sensitivity to measure 0.03 mg/m³, which is 1/10 the concentration of the recommended occupational exposure limit of nanoTiO2 in both stationary sampling and personal exposure sampling settings. In a factory where outside air was directly introduced, micron-sized aggregated particles were generated because of factory operations; however, nanosized and submicron-sized particles were not observed owing to high background concentrations of incidental nanoparticles. Alternatively, in another factory where particles from the outside air were removed using a high-efficiency particulate air filter, work-related nanoparticles were released. The findings of this study suggest that in nanoparticle powder handling processes, a nanoparticle exposure risk exists in the form of nonagglomerated state in nanoparticle powder handling processes.

SARS-CoV-2 genomic surveillance as an evidence-based infection control approach in an offshore petroleum employee population

BACKGROUND

Industrial hygienists (IH) in the oil and gas business instituted an extraordinary number of safety protocols to limit spread of SARS-CoV-2 onto offshore platforms in the Gulf of Mexico. We used genomic surveillance to provide actionable information concerning the efficacy of their efforts.

METHODS

Over 6 months, employees at a single company were serology and PCR tested during a 1-5 day predeployment quarantine and when postdeployment symptoms were reported. From each positive test (n = 49), SARS-CoV-2 genomes were sequenced. Phylogenetic analysis was used to investigate the epidemiology of transmissions.

RESULTS

Genomic surveillance confirmed 2 viral strains were infecting 18 offshore workers. Genomic data combined with epidemiological data suggested that a change in quarantine protocols contributed to these outbreaks. A pre-deployment outbreak involved a WHO variant of interest (Theta) that had infected 4 international workers. Two additional predeployment clusters of infections were identified.

CONCLUSIONS

Our findings support that IH quarantine/testing protocols limited viral transmissions, halted offshore outbreaks, and stopped the spread of a variant of interest. The study demonstrates how genomic data can be used to understand viral transmission dynamics in employee populations and evaluate safety protocols in the offshore oil and gas industry.

[A system for collecting historical professional exposures in the workplace in Piedmont (ESP ALP).]

SUMMARY

Background. ARPA Piemonte carries out occupational exposure measurements of chemical agents in workplace environment to support the Occupatonal Health and Safety Units of Local Health Boards for the assessment of the exposure level of dangerous chemical. Data are reported in internal documents, but are not available for other purposes. Objectives. Organize the occupational exposure measures collected by ARPA Piemonte, in order to facilitate their availability, in accordance with the indications of the European Foundation for the Improvement of Living and Working Conditions. Methods. An application in a relational database environment was defined and developed to collect and structure information relating to companies, interventions, tasks and / or monitored sampling points, samples and measurements performed. Results. Data on chemical exposure related to interventions carried out by ARPA Piemonte in the period from 2005 to part of 2020 have been collected in the ESP ALP application. ESP ALP contains information about 161 companies, 193 interventions, 815 sampling points, 3.490 samples and 18.576 measurements and information on companies obtained from the 2011 Census of Economic Activities and the archives of the National Institute for Insurance against Accidents at Work (INAIL). Discussion. We verified the feasibility of retrieving and organizing the information collected in past years in an integrated environment that facilitates its processing and use. Finally, we confirm the usefulness of collaboration between multidisciplinary professionals.

A real-time gas monitoring system based on ion mobility spectrometry for workplace environmental measurements

A volatile organic compounds (VOC) gas monitor was developed using an ion mobility spectrometer (IMS). It was designed for real-time monitoring in work environments, where gas chromatography/mass spectrometry (GC/MS) does not perform well. To evaluate the identification capability, response time, and quantitative accuracy of this device, experiments were conducted using methyl ethyl ketone. This is widely used in many factories, and its short-term exposure limit (STEL) has been set by the American Conference of Governmental Industrial Hygienists. Because the ionizable amount of methyl ethyl ketone has already been exceeded in STEL value of 300 ppm which belongs to the measurement range of interest in this study, this study estimated the peak shift amount rather than the peak intensity. Calibration curves with high accuracy were obtained in a range including 300 ppm which is the STEL of methyl ethyl ketone. The results of the experiment suggest that the device can be used for monitoring chemical substances in a work environment.

Exposure analysis of benzene in workplace control room A and B PT X

OBJECTIVE

The control room A and B employees are a high risk of benzene exposure, because they work close to the waste pit which is a source of benzene. This study is to analyze the magnitude of the health risk of benzene exposure to all employees.

METHODS

The data of this study were obtained from interviews and the results of environmental quality of PT X. Data were analyzed using Environmental Health Risk Analysis (EHRA) method which compared with RfC for non-carcinogenic effects and CSF for carcinogenic effects.

RESULTS

The results of individual calculations for the non-carcinogenic and carcinogenic effect of benzene are at a dangerous level in both real time and lifetime exposure.

CONCLUSIONS

In the calculation of carcinogenic and non-carcinogenic risk exposure in real time, half the populations are at risk of being affected and in lifetime the entire populations are at risk of being exposed to these effects.

Exposure analysis of lead (Pb) and chromium (Cr) in workplace workshop PT. X

OBJECTIVE

The workshop (pipe repair place) owned by PT. X is potential for heavy metal exposure which can exceed the quality standards. This study is to identify and analyze the risk of heavy metal exposure from the production process and compare it with the quality standards for the workplace that have been set by the government.

METHODS

This research is a quantitative study using the method of environmental health risk analysis (EHRA).

RESULT

The concentration of risk agents that could cause adverse health effects of non-carcinogenic due to lead exposure was 15 workers both realtime and lifetime, chromium exposure was 6 workers in realtime and 15 workers for lifetime. While the results of carcinogenic effects due to lead exposure were 1 worker for lifetime and chromium was 15 workers both realtime and lifetime.

CONCLUSION

Efforts to control heavy metals can be carried out through technical engineering, administrative control, and personal protective equipment.

Management of bias and conflict of interest among occupational exposure limit expert groups

Our aim was to evaluate policies and procedures for management of conflict of interest (CoI) and other sources of bias, implemented in Occupational Exposure Limit (OEL) expert groups. First, we compiled procedural criteria applicable to OEL-setting, based on literature on CoI and systematic reviews. Second, we identified 58 global OEL-sources and sought the underlying expert groups and operating procedures. We identified eleven active groups, of which five have documented CoI policies. In all five, CoI management is based on declarations of interests (DoIs) and removal of experts from decisions in which they have an interest. Notable differences include publication of DoIs (three of five groups), limitation of DoI to current interests (two groups), quantitative limits for financial interests (none specified to ≥€10,000 per interest), control procedures for undisclosed CoI (one group), and procedures in case of discovery of undisclosed CoI (three groups). Methods to evaluate study quality are described by three groups, while reproducible and comprehensive strategies to identify and select data receive less attention. We conclude that procedures to manage CoI and bias are not broadly implemented, or at least not openly and transparently communicated. This lack of visible procedures is remarkable, considering OEL's impact on health and economy.

Exposures during wet production and use processes of nanomaterials: a summary of 11 worksite evaluations

From 2011-2015, the National Institute for Occupational Safety and Health Nanotechnology Field Studies Team conducted 11 evaluations at worksites that either produced engineered nanomaterials (ENMs) via a wet process or used ENMs in a wetted, suspended, or slurry form. Wet handling or processing of ENMs reduces potential exposure compared to dry handling or processing; however, air sampling data indicated exposures may still occur. Information was gathered about each company, production processes, ENMs of interest, and control measures. Exposure assessments included air sampling using filter media, surface wipe sampling, and real-time particle counting by direct-reading instruments. Electron microscopy analysis of air filters confirmed the presence of ENMs of interest (10 of 11 sites). When a method was available, chemical analysis of filters was also used to detect the presence of ENMs (nine of 11 sites). Wipe samples were collected at four of the 11 sites, and, in each case, confirmed the presence of ENMs on surfaces. Direct-reading data showed potential nanomaterial emissions (nine of 11 sites). Engineering controls included fume hoods, cleanrooms, and enclosed processes. Personal protective equipment was required during all 11 evaluations. Recommendations to address potential exposures were provided to each company following the hierarchy of controls.

The Optimization of Methods for the Collection of Aerosolized Murine Norovirus

Globally, norovirus is the most common gastroenteritis causing pathogen. Annually, norovirus causes 685 million cases of acute gastroenteritis and 200,000 deaths, worldwide. Recent evidence has suggested that norovirus can also be spread via aerosolization; however, an indoor generation source has yet to be determined. We optimized a sampling method for the collection of aerosolized norovirus using murine norovirus (MNV) as a surrogate. Optimization of the sampling method was performed using two bioaerosol samplers (SKC BioSampler and the NIOSH Bioaerosol Cyclone Sampler 251) and two sampling media (Hanks Balanced Salt Solution [HBSS] and Phosphate Buffered Saline [PBS]). Murine norovirus was aerosolized in a bioaerosol chamber and later collected using each sampler/media combination. Collected MNV was quantified using quantitative polymerase chain reaction (qPCR). Intact capsids of MNV were assessed using propidium monoazide dye in combination with qPCR and confirmed with transmission electron microscopy. Ten trials were conducted, with each trial lasting for 30 min. The SKC BioSampler collected a significantly higher concentration of MNV than the NIOSH-251 sampler did (p-value < 0.0001). However, there were no significant differences in the relative percent of MNV that remained viable between both samplers (p-value = 0.2215). The use of HBSS sampling media yielded a higher concentration of MNV than PBS media (p-value = 0.0125). However, PBS media maintained viability at a significantly higher percentage than HBSS media (p-value < 0.0001). The results support the optimization of a sampling method for the collection of aerosolized MNV and possibly norovirus in different sampling environments.

A systematic risk-based strategy to select personal protective equipment for infectious diseases

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Selection of personal protective equipment (PPE) can be systematic and risk-based.

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Potential exposures are compared with sites susceptible to infection.

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Facilitates transparent decision-making about personal protective equipment.

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PPE evaluation includes: donning/doffing/changing, usability, and fit for purpose.

Background

Personal protective equipment (PPE) is a primary strategy to protect health care personnel (HCP) from infectious diseases. When transmission-based PPE ensembles are not appropriate, HCP must recognize the transmission pathway of the disease and anticipate the exposures to select PPE. Because guidance for this process is extremely limited, we proposed a systematic, risk-based approach to the selection and evaluation of PPE ensembles to protect HCP against infectious diseases.

Methods

The approach used in this study included the following 4 steps: (1) job hazard analysis, (2) infectious disease hazard analysis, (3) selection of PPE, and (4) evaluation of selected PPE. Selected PPE should protect HCP from exposure, be usable by HCP, and fit for purpose.

Results

The approach was demonstrated for the activity of intubation of a patient with methicillin-resistant Staphylococcus aureus or Severe Acute Respiratory Syndrome coronavirus. As expected, the approach led to the selection of different ensembles of PPE for these 2 pathogens.

Discussion

A systematic risk-based approach to the selection of PPE will help health care facilities and HCP select PPE when transmission-based precautions are not appropriate. Owing to the complexity of PPE ensemble selection and evaluation, a team with expertise in infectious diseases, occupational health, the health care activity, and related disciplines, such as human factors, should be engaged.

Conclusions

Participation, documentation, and transparency are necessary to ensure the decisions can be communicated, critiqued, and understood by HCP.

Bayesian State Space Modeling of Physical Processes in Industrial Hygiene

Exposure assessment models are deterministic models derived from physical-chemical laws. In real workplace settings, chemical concentration measurements can be noisy and indirectly measured. In addition, inference on important parameters such as generation and ventilation rates are usually of interest since they are difficult to obtain. In this article, we outline a flexible Bayesian framework for parameter inference and exposure prediction. In particular, we devise Bayesian state space models by discretizing the differential equation models and incorporating information from observed measurements and expert prior knowledge. At each time point, a new measurement is available that contains some noise, so using the physical model and the available measurements, we try to obtain a more accurate state estimate, which can be called filtering. We consider Monte Carlo sampling methods for parameter estimation and inference under nonlinear and non-Gaussian assumptions. The performance of the different methods is studied on computer-simulated and controlled laboratory-generated data. We consider some commonly used exposure models representing different physical hypotheses. Supplementary materials for this article are available online.

Allergy Development in Adulthood: An Occupational Cohort Study of the Manufacturing of Industrial Enzymes

BACKGROUND

Occupational allergy may serve as a model of allergy development in adults.

OBJECTIVE

We aimed at describing respiratory allergy and IgE sensitization across different exposure strata defined by time, technology, and exposure control.

METHODS

In a retrospective (1970-2017) cohort of industrial enzyme production employees, monitored by an occupational medical center, 5024 individuals were surveyed. Five exposure groups and risk levels for sensitization and allergic disease were analyzed on the basis of demographic characteristics, hiring decade, and smoking status.

RESULTS

Of all persons entering the company 47 years from 1970, 149 developed occupational allergy (incidence rate, 2.72/1000 person-years). In a multivariate cause-specific Cox proportional hazards model, the hazard of allergy was significantly related to decade of recruitment. Compared with the 1970s, the hazard ratio (HR) uniformly decreased from 0.85 (95% CI, 0.57-1.27) in the 1980s to 0.16 (95% CI, 0.05-0.52) in the 2010s. Compared with expected highest exposed group, the HRs were 0.48 (95% CI, 0.31-76) and 0.13 (95% CI, 0.06-0.30) in less exposed production areas and 0.92 (95% CI, 0.48-1.73) and 0.23 (95% CI, 0.10-0.53) in different laboratory areas. The HR of smoking was 2.03 (95% CI, 1.41-2.93). The pattern of sensitizations also showed clear associations to recruitment decade, exposure, and smoking. Among individuals sensitized but not yet allergic, a high IgE level was the only risk factor (HR, 3.03; 95% CI, 1.82-5.04) for subsequent allergy development.

CONCLUSIONS

The impact of exposure is dose-related and linked to the sensitization step, which may subsequently lead to allergy development. For primary prevention of enzyme allergy, exposure control is mandatory and achievable despite increasing production volumes.

The development of a globally acceptable national model for occupational hygiene in Turkey: a modified Delphi study

Background

Although various organizations working in developed countries established the standards and approaches used in occupational hygiene, occupational hygiene professional interests and needs continue to develop in a global context. There is thus an urgent need for expanded occupational hygiene models. For successful field implementation, these models should be based on several sets of criteria, including those related to international standards, various national requirements, and multidisciplinary approaches. This is particularly important for countries in which no occupational hygiene model has been developed. This study thus examined the consensus on occupational hygiene standards among stakeholders in Turkey regarding the development of a national model. A modified Delphi study was conducted among key occupational health experts in Turkey who could aid in the relevant implementation, policy-making, and educational processes for such a model. Participants were selected from various governmental institutions, non-governmental organizations, trade unions, universities, and occupational health practices.

Results

The first-round findings were obtained from open-ended questions. The results revealed several requirements, including the adoption of an international hygiene definition, the official recognition of professional and practical areas in Turkish occupational hygiene, hygienist training methods, priorities, and competent institutions. Second-round findings indicated a consensus rate of over 80% regarding the need for implementation standards, training and education standards, requirements and priorities, and competent institutions for professionals working in the field of occupational hygiene. A third-round and SWOT analysis was also conducted among the group to confirm the consensus issues.

Conclusions

The search for solutions and developmental expectations increases when awareness of internationalization and the need for common global standards increase. This developmental process may provide the basis for an appropriate model in developing countries.

Critique of the ACGIH 2016 derivation of toluene diisocyanate Threshold Limit Values

In 2016, the American Conference of Governmental Industrial Hygienists (ACGIH) lowered the 8-hr Threshold Limit Value - time-weighted average (TLV-TWA) for toluene diisocyanate (TDI) from 5 ppb to 1 ppb, and the 15-min short-term exposure limit (STEL) from 20 ppb to 5 ppb. We evaluated ACGIH's basis for lowering these values. It is our opinion that the ACGIH's evaluation of the evidence for occupational asthma and respiratory effects from TDI exposure does not fully integrate the results of all the available human and animal studies. We found that some studies reported occupational asthma cases at TWAs less than 5 ppb, but these cases were likely caused by peak exposures above 20 ppb. Advances in industrial hygiene have reduced peak exposures and the incidence of upset conditions, such as spills and accidents, in modern TDI facilities. Taken together, the human evidence indicates that adherence to the previous 8-hr TLV-TWA and 15-min STEL (5 ppb and 20 ppb, respectively) prevents most, if not all, cases of occupational asthma, and eliminates or reduces the risk of lung function decrements and other respiratory effects. While limited, the animal literature supports the human evidence and indicates that TDI-induced asthma is a threshold phenomenon. We conclude that ACGIH's decision to lower the TLV-TWA and STEL values for TDI is not adequately supported.

Historical evolution of regulatory standards for occupational and consumer exposures to industrial talc

Talc has been used historically in a wide range of industrial applications and consumer products. The composition and purity of talc used for industrial purposes can vary greatly depending on the source and may contain asbestos minerals. The developing science associated with the health risks of asbestos had an effect on the talc industry throughout the 20th century. This review presents a detailed analysis of the evolution of regulatory standards impacting the use of industrial talc in the U.S. from the early 20th century through the 1990s. While it was recognized by the 1930s that airborne exposures to talc dust at high concentrations could cause lung disease, it was not until later that concerns were raised about the health risks associated with potential occupational exposures to asbestos from industrial talc. Regulatory agencies adopted occupational standards for industrial talc in the early 1970s, but the terminology used to define and characterize talc and other associated minerals varied between agencies. In addition, the complex and varying mineralogy of industrial talc led to inconsistent and imprecise interpretation of studies concerning health risk and occupational health standards among individual agencies.