Silo Gas Exposure in New York State Following the Dry Growing Season of 1995

Abstract

Exposure to silo gas is a recognized agricultural hazard. Silo gas produced from corn fermentation may consist of oxides of nitrogen and carbon dioxide. The presence of potentially lethal concentrations of nitrogen dioxide (NO2) within vertical silos has been well documented. The risk of silo gas exposure from other silage storage methodologies--including horizontal "ag-bags" and concrete bunkers--has been less well characterized. A dry growing season is known to be a factor for elevating nitrate levels in corn plants and can result in increased NO2 production. Farms in the northeastern United States faced drought conditions during the 1995 growing season. The New York State (NYS) Department of Health (DOH) and the New York Center for Agricultural Medicine and Health (NYCAMH) investigated four exposure incidents involving six farmworkers during September/October 1995. Four of these workers were hospitalized for multiple days, with two workers receiving treatment in intensive care units. The remaining two workers were treated in hospital emergency departments; one refused admission and left against medical advice. We monitored NO2 levels from "ag-bags" at several New York farms. For four days, outdoor concentrations of NO2 at one site remained in excess of the National Institute for Occupational Safety and Health's (NIOSH) immediately dangerous to life and health value (IDLH) of 20 ppm. As a result of the clinical and industrial hygiene data, and the growing season's abnormal weather conditions, DOH and NYCAMH issued statewide health hazard alerts and conducted educational activities to warn farmers and their families. The findings of this study reinforce the potential hazards associated with silo gas exposure and identify the use of ag-bags as a relatively new avenue for significant worker exposure.

Climate Change, Drought and Human Health in Canada

“…Dry conditions can increase nitrate levels in corn plants and encourage the accumulation of nitrogen dioxide (NO 2 ), thereby elevating the risk of “silo-filler’s disease” [ 158 ]. A greater number of “silo-filler’s disease” cases were reported in New York State after a dry growing season in 1995 [ 158 ]. There are approximately five cases of silo-filler’s disease per 100,000 silo-associated farm workers in New York State annually [ 159 ].…”

“…Over time new agricultural practices and technologies have increased agricultural output, but have also led to increased costs and vulnerability for farmers during drought [ 83 ]. Given their occupational environment, agricultural workers are at increased risk of “silo-filler’s disease” (NO 2 gas poisoning within silos) [ 158 ]. Horticulturalists and people working for nurseries, garden supply stores and recreational facilities have also been identified as being at higher risk of negative health outcomes [ 46 ].…”

Assessment of personal protective equipment use among Midwestern farmers

“…Handling hay, grain, and silage is a major cause of chronic illness in agricultural workers [Penn State, 1992;Bharadwaj etal.,1999;Kirkhornand Garry, 2000].Entering confined areas such assilos,grain bins, or any inadequatelyventilated building can put a farmer at risk of being overcome by silo gases or dusts which can cause permanent lung damage or death [Douglas et al, 1989;Zwemer et al, 1992;Pavelchak et al, 1999]. Shoveling or grinding grain, or cleaning out grain storage structurescanalsoexposefarmerstobacterialandfungalspores and byproducts.…”

Differential expression of pro-inflammatory and oxidative stress mediators induced by nitrogen dioxide and ozone in primary human bronchial epithelial cells

“…Indoor concentrations of NO 2 , largely attributed to unvented gas combustion sources, often exceed those measured outdoors, and concentrations of NO 2 can reach as high as 1 ppm (WHO, 2005). Other environments where elevated NO 2 concentrations (2–5 ppm) have been found include inside power plants (Carbone et al, 2014) and unvented ice hockey rinks (Pelham et al, 2002, Lee et al, 1994), in the workplaces of welders (Azari et al, 2011), in traffic (Persinger et al, 2002), and directly outside farming silos (Pavelchak et al, 1999). In controlled human exposure studies, acute exposures to NO 2 have resulted in increased PMN production found in bronchial washings (Devlin et al, 1999, Blomberg et al, 1997), suggesting that NO 2 can elicit changes to underlying inflammation-related events in the respiratory system.…”