Steven W. Lenhart

Occupational exposure to airborne endotoxins during poultry processing

Airborne gram-negative bacterial endotoxin levels were quantified in a live chicken hanging (shackling) room of a poultry processing plant. The mean respirable dust levels at the entrance and exit of the shackling line were 1.13 +/- 0.12 and 0.72 +/- 0.06 mg/m3, respectively, or approximately 6% of the total dust. Endotoxins constituted 43.3 +/- 2.8 micrograms per gram of respirable dust. Airborne endotoxins were present in the total dust at the mean level of 918.4 +/- 159.0 ng/m3 at the room entrance and 634.0 +/- 96.9 ng/m3 at the exit, with respirable levels of 44.3 +/- 7.8 and 33.6 +/- 2.2 ng/m3. Inhalation of gram-negative bacterial endotoxins can result in respiratory and systemic pathophysiology. The potential for adverse health effects in the working environment of the live poultry processing industry is discussed. Medical studies of workers in this area are required to confirm or deny the existence of occupationally related health effects.

Respiratory protection as a function of respirator fitting characteristics and fit-test accuracy.

The fitting characteristics of particulate respirators are no longer assessed in the National Institute for Occupational Safety and Health respirator certification program. It is important for respirator program administrators to understand the implications of that change and the additional burden it may impose. To address that issue, a typical respirator fit-testing program is analyzed using a mathematical model that describes the effectiveness of a fit-testing program as a function of the fitting characteristics of the respirator and the accuracy of the fittesting method. The model is used to estimate (1) the respirator assignment error, the percentage of respirator wearers mistakenly assigned an ill-fitting respirator; (2) the number of fit-test trials necessary to qualify a group of workers for respirator use; and (3) the number of workers who will fail the fit-test with any candidate respirator model and thereby fail to qualify for respirator use. Using data from previous studies, the model predicts respirator assignment errors ranging from 0 to 20%, depending on the fitting characteristics of the respirator models selected and the fit-testing method used. This analysis indicates that when respirators do not necessarily have good fitting characteristics, respirator program administrators should exercise increased care in the selection of respirator models and increased care in fit-testing. Also presented are ways to assess the fitting characteristics of candidate respirator models by monitoring the first-time fit-testing results. The model demonstrates that significant public health and economic benefits can result when only respirators having good fitting characteristics are purchased and respirators are assigned to workers using highly accurate fit-testing methods.

Viable sampling for airborne bacteria in a poultry processing plant

Air was sampled for viable bacteria in the shackling room of a poultry processing plant. Large numbers of bacteria were isolated from the workers’ breathing zone, and gram‐negative organisms were characterized. The probable source of airborne gram‐negative bacteria and their endotoxins was identified as the birds’ feces. These data suggest a potential health risk for workers due to inhalation of viable bacteria.

Organic Dust, Endotoxin, and Ammonia Exposures in the North Carolina Poultry Processing Industry

Abstract The growth of the poultry processing industry was possible because of veterinary preventive medicine techniques and improvements in breeding, feed conversion, housing, and marketing practices. Increased production of broilers has caused an increase in the amount of airborne contaminants to which poultry processing workers (growers, catchers, and hangers) are exposed. The purposes of this research were to evaluate the exposures experienced by poultry processing workers in North Carolina and to recommend control measures for reducing exposures below levels considered to be safe. Exposure estimates were compared to 8-hour time-weighted average (TWA) limits of 10 mg/m3 for total dust, 5 mg/m3 for respirable dust, 10 ng/m3 for bacterial endotoxin, and 25 ppm for ammonia with a STEL of 35 ppm. Personal sampling at 22 North Carolina poultry farms involving 26 growers produced geometric mean 8-hour TWA concentrations of 11.6 mg/m3 for inhalable dust, 0.60 mg/m3 for respirable dust, 100 ng/m3 for inhalabl...

Workplace Evaluation of a Disposable Respirator in a Dusty Environment

Abstract Industrial hygiene sampling for total airborne particulate during the manufacture of a concrete patching compound revealed concentration estimates which exceeded the ACGIH TLV of 10 mg/m3. These results led to recommendations for the implementation of improved engineering controls and the initiation of a respiratory protection program on an interim basis. The 3M 9910 disposable respirator was selected for use based upon a knowledge of existing total dust concentrations and a review of assigned protection factors for the various classes of respiratory protective devices. A follow-up evaluation by NIOSH investigators revealed that use of 3M 9910 respirators reduced total dust exposures to levels considered to be acceptable, but that the assigned protection factor derived from a set of workplace protection factors was less than anticipated. The results of this study suggest the need for inmask sampling after the implementation of respiratory protection to ensure, in a direct manner, that the particu...

Application of a Pilot Study to the Development of an Industrial Hygiene Sampling Strategy

An industrial hygiene pilot study was conducted to estimate the concentrations of respirable dust likely to be encountered during the personal sampling phase of a large-scale morbidity study of the portland cement industry. An analysis of the pilot study data showed little variability in exposure for subjects working in the same job in the same area of the same plant. Thus, one could estimate mean exposure by sampling several subjects rather than sampling the same subject several times. It was concluded that for statistical considerations, the best approach would be to sample four jobs per area and six subjects per job. Practical considerations required one more often to select six jobs with two subjects per job, however. Overall, the collection of fewer samples was required during the morbidity study than was anticipated originally. In turn, the reduction in the number of samples to be collected resulted in a savings of time and resources.

Manganese Dioxide Exposures and Respirator Performance at an Alkaline Battery Plant

Two industrial hygiene studies were conducted at an alkaline battery plant to evaluate worker exposures to manganese dioxide particulate and the effectiveness of filtering facepiece respirators. The work areas studied included the plants powder-processing tower and press rooms where manganese was blended, compacted with graphite, and inserted into battery cans. Full-shift personal breathing zone monitoring was conducted to estimate manganese dust exposures of press operators, mechanics, and material handlers. In-facepiece and personal breathing zone air sampling pairs were also collected using a program protection factor protocol to estimate the protection provided by the respirators. Particle size evaluations were made using nylon cyclones and Marple personal multi-stage impactors. All samples were analyzed for manganese by inductively coupled argon plasma, atomic emission spectroscopy via NIOSH analytical method 7300 utilizing a modified acid digestion procedure. Fifty-four, full-shift, time-weighted average (TWA) exposures to total manganese ranged from 0.1 to 5.4 milligrams per cubic meter (mg/m3); worker exposures were substantially lower during a follow-up study due to engineering control improvements. Concurrent area sample comparisons of total and respirable manganese revealed that the respirable particulate mass fractions ranged from 6 to 32 percent, and mass median aerodynamic diameters determined from personal breathing zone air samples were mostly greater than 10 micrometers. Fifteen respirator performance evaluations were conducted using Moldex 2200 respirators fitted with 25 millimeter cassettes and light weight sampling probes. Protection factors ranged from 5 to 220, with a geometric mean and standard deviation of 31 and 2.97, respectively. The 5th percentile protection factor estimate was 5, as calculated from the protection factor distribution for this sample set. In 1995, the American Conference of Governmental Industrial Hygienists (ACGIH) lowered the elemental and inorganic manganese dust Threshold Limit Value (TLV) from 5 mg/m3 to 0.2 mg/m3 to address adverse pulmonary and central nervous system effects and male infertility. Although most personal breathing zone concentrations were above 0.2 mg/m3, none of the in-facepiece concentrations exceeded this concentration. Parkinsons-like symptoms have been reported in the literature for high manganese dust and fume exposures, but the importance of low dust exposures for producing neurological effects is uncertain.

Respiratory Illness in Workers of an Indoor Shiitake Mushroom Farm

Abstract Shiitake mushrooms (Lentinus edodes), the second most important mushroom in world commerce, are usually grown on logs outdoors. Because of the relatively short harvesting period and weather dependency of shiitake strains that are cultivated outdoors, there is a trend toward indoor cultivation of strains that can permit year-round production. An evaluation of an indoor shiitake farm was conducted following reports that workers of the facility were experiencing symptoms of respiratory illness. During private interviews that included the administration of a questionnaire, 11 workers reported seven or more symptoms which they had experienced either during work or shortly after leaving work; six of these workers reported 15 or more symptoms. Predominant symptoms were dry cough, nasal discharge, sneezing, chest tightness, productive cough, and dyspnea. Based upon the results of the acute symptoms questionnaire and preliminary bioaerosol sampling, the management of the shiitake farm discontinued operati...