Lauralynn Taylor McKernan

Occupational safety and health, green chemistry, and sustainability: a review of areas of convergence

With increasing numbers and quantities of chemicals in commerce and use, scientific attention continues to focus on the environmental and public health consequences of chemical production processes and exposures. Concerns about environmental stewardship have been gaining broader traction through emphases on sustainability and “green chemistry” principles. Occupational safety and health has not been fully promoted as a component of environmental sustainability. However, there is a natural convergence of green chemistry/sustainability and occupational safety and health efforts. Addressing both together can have a synergistic effect. Failure to promote this convergence could lead to increasing worker hazards and lack of support for sustainability efforts. The National Institute for Occupational Safety and Health has made a concerted effort involving multiple stakeholders to anticipate and identify potential hazards associated with sustainable practices and green jobs for workers. Examples of potential hazards are presented in case studies with suggested solutions such as implementing the hierarchy of controls and prevention through design principles in green chemistry and green building practices. Practical considerations and strategies for green chemistry, and environmental stewardship could benefit from the incorporation of occupational safety and health concepts which in turn protect affected workers.

Biological exposure assessment to tetrachloroethylene for workers in the dry cleaning industry

BackgroundThe purpose of this study was to assess the feasibility of conducting biological tetrachloroethylene (perchloroethylene, PCE) exposure assessments of dry cleaning employees in conjunction with evaluation of possible PCE health effects.MethodsEighteen women from four dry cleaning facilities in southwestern Ohio were monitored in a pilot study of workers with PCE exposure. Personal breathing zone samples were collected from each employee on two consecutive work days. Biological monitoring included a single measurement of PCE in blood and multiple measurements of pre- and post-shift PCE in exhaled breath and trichloroacetic acid (TCA) in urine.ResultsPost-shift PCE in exhaled breath gradually increased throughout the work week. Statistically significant correlations were observed among the exposure indices. Decreases in PCE in exhaled breath and TCA in urine were observed after two days without exposure to PCE. A mixed-effects model identified statistically significant associations between PCE in exhaled breath and airborne PCE time weighted average (TWA) after adjusting for a random participant effect and fixed effects of time and body mass index.ConclusionAlthough comprehensive, our sampling strategy was challenging to implement due to fluctuating work schedules and the number (pre- and post-shift on three consecutive days) and multiplicity (air, blood, exhaled breath, and urine) of samples collected. PCE in blood is the preferred biological index to monitor exposures, but may make recruitment difficult. PCE TWA sampling is an appropriate surrogate, although more field intensive. Repeated measures of exposure and mixed-effects modeling may be required for future studies due to high within-subject variability. Workers should be monitored over a long enough period of time to allow the use of a lag term.

Monitoring Microbial Populations on Wide-Body Commercial Passenger Aircraft

Although exposure to bacteria has been assessed in cabin air previously, minimal numbers of samples have been collected in-flight. The purpose of this research was to comprehensively characterize bacterial concentrations in the aircraft cabin. Twelve randomly selected flights were sampled on Boeing-767 aircraft, each with a flight duration between 4.5 and 6.5 h. N-6 impactors were used to collect sequential, triplicate air samples in the front and rear of coach class during six sampling intervals throughout each flight: boarding, mid-climb, early cruise, mid-cruise, late cruise and deplaning. Comparison air samples were also collected inside and outside the airport terminals at the origin and destination cities. The MIXED procedure in SAS was used to model the mean and the covariance matrix of the natural log-transformed bacterial concentrations. A total of 513 airborne culturable bacterial samples were collected. During flight (mid-climb and cruise intervals), a model-adjusted geometric mean (GM) of 136 total colony-forming units per cubic meter of air sampled (CFU x m(-3)) and geometric standard deviation of 2.1 were observed. Bacterial concentrations were highest during the boarding (GM 290 CFU x m(-3)) and deplaning (GM 549 CFU x m(-3)) processes. Total bacterial concentrations observed during flight were significantly lower than GMs for boarding and deplaning (P values <0.0001-0.021) in the modeled results. Our findings highlight the fact that aerobiological concentrations can be dynamic and underscore the importance of appropriate sample size and design. The genera analysis indicates that passenger activity and high occupant density contribute to airborne bacterial generation. Overall, our research demonstrates that the bacteria recovered on observed flights were either common skin-surface organisms (primarily gram-positive cocci) or organisms common in dust and outdoor air.

Flavoring exposure in food manufacturing

Flavorings are substances that alter or enhance the taste of food. Workers in the food-manufacturing industry, where flavorings are added to many products, may be exposed to any number of flavoring compounds. Although thousands of flavoring substances are in use, little is known about most of these in terms of worker health effects, and few have occupational exposure guidelines. Exposure assessment surveys were conducted at nine food production facilities and one flavor manufacturer where a total of 105 area and 74 personal samples were collected for 13 flavoring compounds including five ketones, five aldehydes, and three acids. The majority of the samples were below the limit of detection (LOD) for most compounds. Diacetyl had eight area and four personal samples above the LOD, whereas 2,3-pentanedione had three area samples above the LOD. The detectable values ranged from 25–3124 ppb and 15–172 ppb for diacetyl and 2,3-pentanedione respectively. These values exceed the proposed National Institute for Occupational Safety and Health (NIOSH) recommended exposure limit for these compounds. The aldehydes had the most detectable samples, with each of them having >50% of the samples above the LOD. Acetaldehyde had all but two samples above the LOD, however, these samples were below the OSHA PEL. It appears that in the food-manufacturing facilities surveyed here, exposure to the ketones occurs infrequently, however levels above the proposed NIOSH REL were found. Conversely, aldehyde exposure appears to be ubiquitous.

Exposure Estimation and Interpretation of Occupational Risk: Enhanced Information for the Occupational Risk Manager

The fundamental goal of this article is to describe, define, and analyze the components of the risk characterization process for occupational exposures. Current methods are described for the probabilistic characterization of exposure, including newer techniques that have increasing applications for assessing data from occupational exposure scenarios. In addition, since the probability of health effects reflects variability in the exposure estimate as well as the dose-response curve—the integrated considerations of variability surrounding both components of the risk characterization provide greater information to the occupational hygienist. Probabilistic tools provide a more informed view of exposure as compared to use of discrete point estimates for these inputs to the risk characterization process. Active use of such tools for exposure and risk assessment will lead to a scientifically supported worker health protection program. Understanding the bases for an occupational risk assessment, focusing on important sources of variability and uncertainty enables characterizing occupational risk in terms of a probability, rather than a binary decision of acceptable risk or unacceptable risk. A critical review of existing methods highlights several conclusions: (1) exposure estimates and the dose-response are impacted by both variability and uncertainty and a well-developed risk characterization reflects and communicates this consideration; (2) occupational risk is probabilistic in nature and most accurately considered as a distribution, not a point estimate; and (3) occupational hygienists have a variety of tools available to incorporate concepts of risk characterization into occupational health and practice.

Analytical Performance Criteria: Field Evaluation of Diacetyl Sampling and Analytical Methods

D iacetyl and acetoin are ketones that are used extensively in the flavoring and food production industries. Both compounds are monitored in the workplace to assess exposures, to aid in the selection of respirators, and to evaluate the effectiveness of ventilation and other control procedures. Researchers from the National Institute for Occupational Safety and Health (NIOSH) published methods to sample and analyze airborne concentrations of diacetyl and acetoin in workplaces.(1) Recent laboratory investigations indicate that the diacetyl method is affected by humidity, resulting in an underestimation of true diacetyl concentration.(2) The effects of humidity on the collection and subsequent desorption of organic compounds on solid sorbent media has been investigated previously. McCammon and Woebkenberg(3) describe the effects of humidity on both silica gel and carbon molecular sieve. The polar nature of silica gel causes it to both adsorb water vapor and show a decrease in breakthrough capacity for non-water-soluble substances with increasing humidity. Carbon molecular sieves retain adsorbed species according to molecular size, and small organic compounds with molecular size similar to water must compete for sorption sites in an equilibrium at least partially based on concentration, which favors adsorption of water. In a study more specific to this effect, Karbiwnyk et al.(4) found that water vapor can interfere significantly in the measurement of volatile organic compounds using solid sorbents of varying hydrophobic characteristics. That interference is attributed to a reduction in retention of analyte during sampling. A compound-specific change in minimum detectable level of analyte with increase in humidity was seen using an Environmental Protection Agency Carbotrap/Carboxen 1000 method,(5) although this change produced both increased as well as decreased detection levels. Similarly, a study of dual phase (vapor/particulate) pesticide sampling(6) concluded that a competitive mechanism seems to exist “between water molecules in gas phase and pesticides to adsorb on the receiving sites of the particles.” The effect of humidity on the collection of volatile polar organic compounds using carbon molecular sieve tubes may have a threshold below which humidity is not an issue, although that threshold seems to vary with sorbent material and possibly with analyte.(7) To aid in the evaluation of sampling and analytical methods for diacetyl, a field comparison between new and existing sampling collection methods was conducted. Side-by-side field samples were collected and analyzed according to NIOSH method 2557, OSHA method PV 2118, and a modified version of the Occupational Safety and Health Administration (OSHA) method. Because many of these samples were analyzed for acetoin as well as diacetyl, data are presented for both measurements in this report.

Translation research in occupational safety and health: A proposed framework

Translation research in occupational safety and health is the application of scientific investigative approaches to study how the outputs of basic and applied research can be effectively translated into practice and have an impact. This includes the study of the ways in which useful knowledge and interventions are disseminated, adopted, implemented, and institutionalized. In this paper, a 4-stage framework (Development, Testing, Institutionalization, and Evaluation) is presented. Translation research can be used to enhance the use and impact of occupational safety and health knowledge and interventions to protect workers. This type of research has not received much attention in the occupational safety and health field. However, in contemporary society, it is critical to know how to make an impact with the findings and outputs of basic and applied research. This paper provides a novel framework for consideration of how to advance and prioritize translation research for occupational safety and health.

State-of-the-Science: The Evolution of Occupational Exposure Limit Derivation and Application

This article not subject to U.S. copyright law. This is an Open Access article. Non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly attributed, cited, and is not altered, transformed, or built upon in any way, is permitted. The moral rights of the named author(s) have been asserted. Address correspondence to Thomas J. Lentz, National Institute for Occupational Safety and Health, 1090 Tusculum Avenue, MS C-32, Cincinnati, Ohio 45226; e-mail: TLentz@cdc.gov

Assessing Total Fungal Concentrations on Commercial Passenger Aircraft Using Mixed-Effects Modeling

The primary objective of this study was to compare airborne fungal concentrations onboard commercial passenger aircraft at various in-flight times with concentrations measured inside and outside airport terminals. A secondary objective was to investigate the use of mixed-effects modeling of repeat measures from multiple sampling intervals and locations. Sequential triplicate culturable and total spore samples were collected on wide-body commercial passenger aircraft (n = 12) in the front and rear of coach class during six sampling intervals: boarding, midclimb, early cruise, midcruise, late cruise, and deplaning. Comparison samples were collected inside and outside airport terminals at the origin and destination cities. The MIXED procedure in SAS was used to model the mean and the covariance matrix of the natural log transformed fungal concentrations. Five covariance structures were tested to determine the appropriate models for analysis. Fixed effects considered included the sampling interval and, for samples obtained onboard the aircraft, location (front/rear of coach section), occupancy rate, and carbon dioxide concentrations. Overall, both total culturable and total spore fungal concentrations were low while the aircraft were in flight. No statistical difference was observed between measurements made in the front and rear sections of the coach cabin for either culturable or total spore concentrations. Both culturable and total spore concentrations were significantly higher outside the airport terminal compared with inside the airport terminal (p-value < 0.0001) and inside the aircraft (p-value < 0.0001). On the aircraft, the majority of total fungal exposure occurred during the boarding and deplaning processes, when the aircraft utilized ancillary ventilation and passenger activity was at its peak.

Erratum: Flavoring exposure in food manufacturing

Correction to: Journal of Exposure Science and Environmental Epidemiology (2014). doi:10.1038/jes.2014.52; published online 23 July 2014 The following funding source for this article was unintentionally omitted: “This study was supported in part by an interagency agreement between the National Institute for Occupational Safety and Health (NIOSH) and the National Institute of Environmental Health Sciences (NIEHS) (Y1-ES-9018-02) as a collaborative National Toxicology Program research activity.