Pavelchak N, Church L, Roerig S, London M, Welles W, Casey G
New York State Department of Health, Albany, New York, USA.
Appl Occup Environ Hyg. 1999 Jan;14(1):34-8. doi: 10.1080/104732299303395.
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.
接触青贮窖气体是一种公认的农业危害。玉米发酵产生的青贮窖气体可能包含氮氧化物和二氧化碳。垂直青贮窖内存在潜在致命浓度的二氧化氮（NO₂）已有充分记录。来自其他青贮储存方法（包括卧式“农业袋”和混凝土料仓）的青贮窖气体暴露风险的特征描述较少。已知干旱生长季节是提高玉米植株硝酸盐水平的一个因素，并且可能导致二氧化氮产量增加。美国东北部的农场在1995年生长季节面临干旱状况。纽约州（NYS）卫生部（DOH）和纽约农业医学与健康中心（NYCAMH）调查了1995年9月/10月期间涉及六名农场工人的四起暴露事件。其中四名工人住院多日，两名工人在重症监护病房接受治疗。其余两名工人在医院急诊科接受治疗；一名工人拒绝入院并自行离院。我们监测了纽约几个农场“农业袋”中的二氧化氮水平。在一个地点，室外二氧化氮浓度连续四天超过美国国家职业安全与健康研究所（NIOSH）规定的对生命和健康立即危险值（IDLH）20 ppm。根据临床和工业卫生数据以及生长季节异常的天气状况，纽约州卫生部和纽约农业医学与健康中心发布了全州范围的健康危害警报，并开展了教育活动以警告农民及其家人。这项研究的结果强化了与青贮窖气体暴露相关的潜在危害，并确定了使用“农业袋”是工人大量暴露的一个相对较新的途径。
