An Assessment of Gases in Oxygen-Deficient Hay Silos and the Effects of Forced Ventilation

Details

• Personal Author:
  Clark RE ; Kedan G ; Sjostrom T ; Spielholz P ; Trenary B
• Description:
  Many modern tower silos used in the agricultural industry for hay and grain storage are oxygen-limiting by design. Forced-air ventilation using a forage blower is a method commonly used to decrease concentrations of toxic and asphyxiant gases and to increase the O2 content within a silo headspace prior to worker entry. This article describes the methods used to measure gas concentrations and the results obtained from a pilot study by the Washington Fatality Assessment and Control Evaluation (FACE) program of two oxygen-limiting forage tower silos in eastern Washington State. The silos were monitored for oxygen (O2), nitrogen dioxide (NO2), and carbon dioxide (CO2). Measured O2 concentrations were low in all areas of the headspaces monitored for both silos. After beginning forced-air ventilation, O2 concentrations within the silo headspace returned to ambient levels within 8 to 20 min. Nitrogen dioxide levels exceeded the Washington Industrial Safety and Health Act (WISHA) short-term exposure limit (STEL) in the silo that was filled six days earlier (silo 2), but not in the silo that was filled four days earlier (silo 1). The NO2 concentration in silo 2 decreased to below the WISHA STEL within 15 min of starting ventilation but began to rise shortly after ventilation was stopped. Carbon dioxide, which was only measured in silo 1, was detected at 2% within the headspace of this silo. The carbon dioxide concentration decreased to <1% within 3 min of starting ventilation. [Description provided by NIOSH]
• Subjects:
  Agriculture Confined Spaces Farmers Occupational Health Safety Ventilation
• Keywords:
  Agricultural-industry Agricultural-workers Author Keywords: Gases Confined-spaces Gas-sampling Gases Measurement Sampling Silos Ventilation-equipment
• Series:
  Fatality Assessment and Control Evaluation Reports (FACE)
• ISSN:
  1074-7583
• Document Type:
  Text
• Funding:
  Cooperative Agreement
• Genre:
  Journal Article
• Place as Subject:
  OSHA Region 10 ; Washington
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  83-95
• Volume:
  13
• Issue:
  1
• NIOSHTIC Number:
  nn:20031756
• Citation:
  J Agric Saf Health 2007 Feb; 13(1):83-95
• Federal Fiscal Year:
  2007
• Performing Organization:
  Washington State Department of Labor and Industries
• Peer Reviewed:
  True
• Start Date:
  20040901
• Source Full Name:
  Journal of Agricultural Safety and Health
• End Date:
  20070831
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:90ef576df329f6a0d8d7a2538798633615f9ab28ee7f4f1107b59df75cff0e06a765763bc49fad6a5c87286304e8e4f25eae8d8d85bfb278c39023e57019962a
• Download URL:
  https://stacks.cdc.gov/view/cdc/228565/cdc_228565_DS1.pdf
• File Type:
  [PDF - 249.06 KB ]