Mark Greskevitch

Respiratory Disease in Agricultural Workers: Mortality and Morbidity Statistics

ABSTRACT To quantify the respiratory disease burden among agricultural workers, we examined the 1988–1998 National Center for Health Statistics (NCHS) “Multiple Cause of Death Data” and the 1988–1994 Third National Health and Nutrition Examination Survey data (NHANES III). Proportionate mortality ratios (PMRs) were determined for 11 respiratory conditions among 6 agricultural groups: crop farm workers, livestock farm workers, farm managers, landscape and horticultural workers, forestry workers, and fishery workers. Prevalence ratios (PRs) were determined for 12 respiratory conditions among 3 agricultural groups: farm workers, farm managers, and other agricultural workers. Disease categories groups were based on the 9th International Classification of Diseases and the agricultural groups on the NCHS or NHANES III industry and occupation codes, respectively. Crop farm workers and livestock farm workers had significantly elevated mortality for several respiratory conditions, with mortality for hypersensitivity pneumonitis being 10 and 50 times higher than expected. Landscape and horticultural workers had significantly elevated mortality for abscess of the lung and mediastinum and chronic airways obstruction. Forestry workers had significantly elevated mortality for pulmonary tuberculosis, chronic airways obstruction, and pneumonia. Prevalence of wheeze was elevated for female farm workers, shortness of breath was elevated for farm workers who had ever smoked, and hay fever was elevated for black, non-Hispanic farm workers. Prevalence of asthma was elevated for other agricultural workers who had ever smoked. Farm workers had a PR of 173 for obstructive respiratory abnormality. Continued improvement in occupational health surveillance systems for agriculture is essential to help guide prevention efforts for respiratory disease.

A Survey of Private Sector Respirator Use in the United States: An Overview of Findings

Limitations of previous surveys of respirator use led the National Institute for Occupational Safety and Health (NIOSH) and the Bureau of Labor Statistics to undertake a survey of respirator use and practices among U.S. private sector employers. The survey was mailed to 40,002 private sector establishments in August 2001; the responses were used to develop national estimates. Respirator use was required in 4.5% of establishments and for 3.1% of employees. Of the establishments requiring respirator use, 95% used air-purifying respirators and 17% used air-supplied respirators. Manufacturing; mining (including oil and gas extraction); construction; and agriculture, forestry, and fishing had the highest rates of establishment respirator use. Respirators were used most frequently to protect against dust/mist, paint vapors, and solvents. Large percentages of establishments requiring respirator use had indicators of potentially inadequate respirator programs. Of establishments requiring respirator use, 91% had at least one indicator of a potentially inadequate respiratory protection program, while 54% had at least five indicators. The survey findings suggest that large numbers of employers may not follow NIOSH recommendations and Occupational Safety and Health Administration (OSHA) and Mine Safety and Health Administration (MSHA) requirements for the selection and use of respirators, potentially putting workers at risk. The findings will aid efforts to increase the appropriate use of respirators in the workplace.

COMPARATIVE PULMONARY TOXICITY OF BLASTING SAND AND FIVE SUBSTITUTE ABRASIVE BLASTING AGENTS

Blasting sand is used for abrasive blasting, but its inhalation is associated with pulmonary inflammation and fibrosis. Consequently, safer substitute materials for blasting sand are needed. In a previous study from this laboratory, the comparative pulmonary toxicity of five abrasive blasting substitutes and blasting sand was reported. In this study, the pulmonary toxicity of blasting sand was compared to five additional abrasive blasting substitutes: steel grit, copper slag, nickel slag, crushed glass, and olivine. Exposed rats received by intratracheal instillation 10 mg of respirable-size particles of blasting sand or an abrasive blasting substitute, while controls were instilled with vehicle. Pulmonary inflammation, damage, and fibrosis were examined 28 d postexposure. Pulmonary inflammation was monitored by determining bronchoalveolar lavage polymorphonuclear cell counts and alveolar macrophage activation by chemiluminescence. Pulmonary damage was assessed by acellular bronchoalveolar (BAL) fluid serum albumin concentrations and lactate dehydrogenase activities. Histological examination of lung tissue samples was made to assess the severity and distribution of pulmonary fibrosis, alveolitis, and alveolar epithelial cell hypertrophy and hyperplasia. In comparison to blasting sand, olivine exposed rats had higher levels of pulmonary inflammation and damage with a similar level of fibrosis. Steel grit-exposed rats had lower levels of pulmonary inflammation and damage, and did not develop fibrosis. However, steel grit-exposed rats had a level of epithelial cell hypertrophy and hyperplasia similar to blasting sand. The other abrasive blasting substitutes gave a mixed profile of toxicity. The data demonstrate that steel grit produced less acute pulmonary toxicity than blasting sand or any of the other abrasive blasting substitutes. Notwithstanding, the data also suggest that chronic exposure to steel grit may pose a health risk due to its effects on epithelial cell proliferation in the lung.

Abrasive Blasting Agents: Designing Studies to Evaluate Relative Risk

Workers exposed to respirable crystalline silica used in abrasive blasting are at increased risk of developing a debilitating and often fatal fibrotic lung disease called silicosis. The National Institute for Occupational Safety and Health (NIOSH) recommends that silica sand be prohibited as abrasive blasting material and that less hazardous materials be used in blasting operations. However, data are needed on the relative risks associated with exposure to abrasive blasting materials other than silica. NIOSH has completed acute studies in rats (Hubbs et al., 2001; Porter et al., 2002). To provide dose-response data applicable to making recommendation for occupational exposure limits, NIOSH has collaborated with the National Toxicology Program (NTP) to design longer term studies with silica substitutes. For risk assessment purposes, selected doses will include concentrations that are relevant to human exposures. Rat lung burdens achieved should be comparable to those estimated in humans with working lifetime exposures, even if this results in “overloading” doses in rats. To quantify both dose and response, retained particle burdens in the lungs and lung-associated lymph nodes will be measured, as well as biochemical and pathological indices of pulmonary response. This design will facilitate assessment of the pulmonary fibrogenic potential of inhaled abrasive blasting agents at occupationally relevant concentrations.

Respirator Use and Practices in Agricultural Crop Production Establishments

ABSTRACT The risk of developing respiratory diseases can be reduced by either wearing respiratory protection under the guidance of an effective respiratory protection program or using controls. In 2001, the Survey of Respirator Use and Practices gathered information on the types of respirators used, respirator use practices, and the respirator program characteristics from 40,002 randomly selected US establishments. This report presents findings of the Survey of Respirator Use and Practices for the Agricultural Production—Crops industry and compares them with National Institute for Occupational Safety and Health (NIOSH) recommendations. Approximately one third of all Agricultural Production—Crops establishments required respirator use. Of the Agricultural Production—Crops establishments that required respirator use, (1) a written program to determine what type of respirator to use was not adopted by management in 73% of the establishments; (2) 21% did not know whether air sampling was conducted for substances for which employees were required to use respirators; (3) 29.5% did not provide respirator training for employees; (4) employees were not assessed for medical fitness to wear a respirator or it was not known whether the employees were assessed, in 49.4%; and (5) the program administrator had received no respirator training in 29.5%. Of the Agricultural Production—Crops establishments that required respirator use, 69.5% had at least 3 indicators of a potentially inadequate respiratory protection program. The high rates of indicators of potential inadequacies suggest widespread problems with respiratory protection programs in the Agricultural Production—Crops industry, indicating a potential for improvement.

Respirator Use Among US Farm Operators: Evidence from the 2006 Farm and Ranch Safety Survey

ABSTRACT The objective of this study was to estimate the national prevalence of respirator use among primary farm operators in the United States. The authors analyzed the 2006 Farm and Ranch Safety Survey data collected for 12,278 actively farming primary farm operators. Weighted prevalence and adjusted prevalence ratios (PRs) of respirator use were calculated by farm operator characteristics, farm characteristics, and selected exposures/hazards. Of the estimated 2.1 million farm operators, 37.2% used a respirator on their farm. Respirator use prevalence was significantly higher among operators aged 16–34 years than those aged ≥65 years (46.9% vs. 30.0%; PR = 1.6); male than female operators (39.0% vs. 24.4%; PR = 1.6); operators managing crop farms than operators managing livestock farms (40.9% vs. 33.7%; PR = 1.2); and operators managing farms with value of sales ≥

Quartz Analyses of the Bulk Dust Samples Collected by the National Occupational Health Survey of Mining

100,000 than operators managing farms with value of sales ≤

Comparative Pulmonary Toxicity of 6 Abrasive Blasting Agents

9999 (57.4% vs. 31.4%; PR = 1.8). Of the operators who used a respirator, 69.9% used while working in a dusty environment, 22.6% used while applying/handling pesticides, and 30.4% used while doing other farm-related activities. These results show that an estimated one third of operators used respirators in 2006, and respirator use is most frequent among operators working in a dusty environment. Additional research identifying specific exposures for which respirators or dust masks are used, barriers to respirator or dust mask use, motivators for wearing respirators, and opportunities to increase the use of respiratory protection among farm operators, particularly on smaller farms, is needed.

In vitro toxicity of silica substitutes used for abrasive blasting.

The National Institute for Occupational Safety and Health (NIOSH) conducted the National Occupational Health Survey of Mining (NOHSM) over a 6-year period, which began in May 1984 and ended in Augu...