David M. Zalk

History and Evolution of Control Banding: A Review

Control banding (CB) strategies offer simplified solutions for controlling worker exposures to constituents often encountered in the workplace. The original CB model was developed within the pharmaceutical industry; however, the modern movement involves models developed for non-experts to input hazard and exposure potential information for bulk chemical processes, receiving control advice as a result. The CB approach utilizes these models for the dissemination of qualitative and semiquantitative risk assessment tools being developed to complement the traditional industrial hygiene model of air sampling and analysis. It is being applied and tested in small- and medium-sized enterprises within developed countries and industrially developing countries; however, large enterprises have also incorporated these strategies within chemical safety programs. Existing research of the components of the most available CB model, the Control of Substances Hazardous to Health Essentials, has shown that exposure bands do not always provide adequate margins of safety, that there is a high rate of under-control errors, that it works better with dusts than with vapors, that there is an inherent inaccuracy in estimating variability, and that when taken together the outcomes of this model may lead to potentially inappropriate workplace confidence in chemical exposure reduction in some operations. Alternatively, large-scale comparisons of industry exposure data to this CB models outcomes have indicated more promising results with a high correlation seen internationally. With the accuracy of the toxicological ratings and hazard band classification currently in question, their proper re-evaluation will be of great benefit to the reliability of existing and future CB models. The need for a more complete analysis of CB model components and, most importantly, a more comprehensive prospective research process remains. This analysis will be important in understanding implications of the models overall effectiveness. Since the CB approach is now being used worldwide with an even broader implementation in progress, further research toward understanding its strengths and weaknesses will assist in its further refinement and confidence in its ongoing utility.

The Global Landscape of Occupational Exposure Limits—Implementation of Harmonization Principles to Guide Limit Selection

Occupational exposure limits (OELs) serve as health-based benchmarks against which measured or estimated workplace exposures can be compared. In the years since the introduction of OELs to public health practice, both developed and developing countries have established processes for deriving, setting, and using OELs to protect workers exposed to hazardous chemicals. These processes vary widely, however, and have thus resulted in a confusing international landscape for identifying and applying such limits in workplaces. The occupational hygienist will encounter significant overlap in coverage among organizations for many chemicals, while other important chemicals have OELs developed by few, if any, organizations. Where multiple organizations have published an OEL, the derived value often varies considerably—reflecting differences in both risk policy and risk assessment methodology as well as access to available pertinent data. This article explores the underlying reasons for variability in OELs, and recommends the harmonization of risk-based methods used by OEL-deriving organizations. A framework is also proposed for the identification and systematic evaluation of OEL resources, which occupational hygienists can use to support risk characterization and risk management decisions in situations where multiple potentially relevant OELs exist.

Comparison of Total Dust/Inhalable Dust Sampling Methods for the Evaluation of Airborne Wood Dust

Abstract This article describes a comparison of sampling results from air monitoring conducted using total dust and inhalable dust sampling methodologies for the evaluation of wood dust exposures in a carpenter shop. While it is recognized that the total dust sampling method underestimates the true total inhalable aerosol, and it is desirable to select a sampling method for wood dust that accurately measures inhalable particulate, the results presented in this article indicate that the currently available inhalable dust sampling method may not be reliable for the evaluation of wood dust exposures, particularly at low concentrations. Traditional personal total dust sampling was performed in accordance with National Institute for Occupational Safety and Health Method 0500, and side-by-side comparison sampling was performed with SKC[rgrave] brand inhalable particulate mass (IPM) samplers in accordance with American Conference of Governmental Industrial Hygienists criteria. A total of 25 sample pairs (17 pers...

Carpenter Shop Wood Dust Control: Practical Experience to Reduce Hardwood Dust Exposures Below the American Conference of Governmental Industrial Hygienists Threshold Limit Values

Abstract This article describes the process that was necessary to reduce hardwood dust exposures in a carpenter shop to levels below the current American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value (TLV). Air monitoring included traditional personal sampling for total dust in accordance with the National Institute for Occupational Safety and Health Method 0500. Achieving the ACGIH TLV of 1 mg/m3 for hardwood dust in a typical carpenter shop has been demonstrated to be possible but very difficult. The implemented shop improvements focused on engineering controls and work practice improvements. Reducing most personal wood dust exposures below 2 mg/m3 was accomplished relatively easily; however, reducing the exposures below 1 mg/m3 was considerably more difficult and expensive. A preliminary quantitative comparison of available dust control equipment with hand-held power sanders was also performed. Sanding tool use guidelines were developed from these data to reduce airborn...

Risk Assessment Using Control Banding

Abstract Control banding (CB) strategies offer simplified processes for controlling worker exposures in the absence of firm toxicologic and exposure information. The nanotechnology industry, with overwhelming uncertainties of work-related health risks posed by nanomaterials, is an excellent candidate for applying such strategies. Ongoing surveys continue to reflect that a majority of nanomaterial producers are not performing a basic risk assessment of their products in use. The use of CB strategies has become a primary route for the assessment and prioritization of potential health risks resulting from work-related exposures to nanomaterials and as a pragmatic approach to preliminary risk management. There has been an impressive growth of available CB tools developed internationally to address chemical risk assessment requirements; however, this is especially applicable in the nanomaterial industries. Toward this end, the International Organization for Standardization (ISO) issued a new technical specification standard on the use of CB for managing inhalation risk from engineered nanomaterials. Included in this ISO standard is the CB Nanotool, the first useable tool developed for assessing and controlling nanomaterial exposure risks, which has now received an independent quantitative validation. Research on CB tools has also continued to expand in the scientific literature, and these updates have been addressed in a number of studies. The continuing expansion of CB tool use for nanomaterials requires ongoing efforts for evaluation, validation, and verification. This process has been especially true for the CB Nanotool and includes topics such as its input factors, structure, weighting of risk factors, effectiveness in practice, and utility for exposure mitigation. The ongoing scientific investigation and research on the CB tools developed for nanomaterials is necessary to ensure that risk assessments reflect appropriate solution outcomes and that these CB strategies remain accessible, affordable, and ultimately effective in protecting workers as the science of nanomaterials continues to grow.

Inhibiting the Transport of Hazardous Spores Using Polymer-Based Solutions

A series of polymer solutions were developed for the purpose of immobilizing aerosolized 1–10 μ m sized hazardous biological particles. The polymer solutions were designed as tools for emergency response and remediation personnel. The inhibition of secondary aerosolization and migration of biothreat particles has important implications for public health protection and contamination cleanup. Limiting further dispersion of particles such as Bacillus anthracis spores may reduce inhalation hazards and enhance remediation efficiencies. This study evaluated film-forming polymers that have multiple functional groups capable of attracting and binding particles; these included acrylates, cellulosics, vinyl polymers, and polyurethanes. The selected polymers were combined with appropriate solvents to design solutions that met specific performance objectives. The polymer solutions were then evaluated for key characteristics, such as high adhesion, high elasticity, low density, short drying time, low viscosity, and low surface tension. These solutions were also evaluated for their adhesion to biothreat agent in a series of wind tunnel experiments using highly refined aerosolized Bacillus atrophaeus spores (a simulant for anthrax, 1–3 μ m). Results demonstrated that a polymer solution, an amphoteric acrylate identified as NS-2, was the best candidate for attaching to spores and inhibiting reaerosolization. This polymer solution was anionic, thus providing the electrostatic (coulombic) attraction to cationic spores, had low surface tension, and performed well in wind tunnel tests.

Chapter 6 – Risk Assessment Using Control Banding

Control banding (CB) strategies offer simplified processes for controlling worker exposures in the absence of firm toxicologic and exposure information. The nanotechnology industry, with overwhelming uncertainties of work-related health risks posed by nanomaterials, is an excellent candidate for applying such strategies. Ongoing surveys continue to reflect that a majority of nanomaterial producers are not performing a basic risk assessment of their products in use. The use of CB strategies has become a primary route for the assessment and prioritization of potential health risks resulting from work-related exposures to nanomaterials and as a pragmatic approach to preliminary risk management. There has been an impressive growth of available CB tools developed internationally to address chemical risk assessment requirements; however, this is especially applicable in the nanomaterial industries. Toward this end, the International Organization for Standardization (ISO) issued a new technical specification standard on the use of CB for managing inhalation risk from engineered nanomaterials. Included in this ISO standard is the CB Nanotool, the first useable tool developed for assessing and controlling nanomaterial exposure risks, which has now received an independent quantitative validation. Research on CB tools has also continued to expand in the scientific literature, and these updates have been addressed in a number of studies. The continuing expansion of CB tool use for nanomaterials requires ongoing efforts for evaluation, validation, and verification. This process has been especially true for the CB Nanotool and includes topics such as its input factors, structure, weighting of risk factors, effectiveness in practice, and utility for exposure mitigation. The ongoing scientific investigation and research on the CB tools developed for nanomaterials is necessary to ensure that risk assessments reflect appropriate solution outcomes and that these CB strategies remain accessible, affordable, and ultimately effective in protecting workers as the science of nanomaterials continues to grow.