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Project Details

Occupational Health and Safety: Worker Hazards in Confined Spaces

Workers entering a confined space face a host of potentially lethal hazards.
Project Summary: 

Every day in the U.S., workers enter confined spaces, such as tanks, pipes and trenches, which can contain toxic or oxygen-deficient atmospheres as well as a range of physical hazards. Our research shows that during the period 1990-2005, toxic or oxygen-deficient atmospheres in confined spaces in the U.S. claimed the lives of 530 workers in 431 separate incidents. We found that 57% of surveyed employers did not have an emergency response plan in place to rescue a worker from a confined space, aside from calling the fire department. We found, however, that a fire department rescue from a confined space takes between one and three hours after a call is placed to 911 by the employer, which is far too long to save the life of a worker who experiences an emergency during a confine space entry. Nearly all of the fatalities we investigated were preventable with improved awareness and training, and in some case, the use of safer chemistries.

UC Berkeley Feature Story, February 13, 2012:

Main Findings: 

Between 1992 and 2005, 431 confined space incidents that met the case definition claimed 530 lives, or about 0.63% of the 84,446 all-cause U.S. occupational fatal injuries that occurred during this period. 87 (20%) incidents resulted in multiple fatalities. Twelve (57%) of 21 surveyed companies reported that they relied on the fire department for permit-required confined space emergency response. The median fire department arrival time was about 5 minutes for engines and 7 minutes for technical rescue units. Fire department confined space rescue time estimates ranged from 48 to 123 minutes and increased to 70 and 173 minutes when hazardous materials were present. Our work illustrates that: (i) confined space incidents represent a small but continuing source of fatal occupational injuries in the U.S.; (ii) a sizeable portion of employers may be relying on public fire departments for permit-required confined space emergency response; and (iii) in the event of a life-threatening emergency, fire departments usually are not able to effect a confined space rescue in a timely manner. We propose that the appropriate role for the fire department is to support a properly trained and equipped on-site rescue team, and to provide advanced life support intervention following extrication and during ambulance transportation.

Policy, Practice or Research Impacts: 

In response to 7 recent confined space fatalities in California and the findings of this paper, Cal/OSHA launched a special emphasis program in confined space safety in February 2012 (see

The California Department of Public Health, Occupational Health Branch issued two Health Hazard Advisories:

  1. Worker Fatality Alert: Methylene chloride linked to worker death in tank
  2. Methylene chloride is dangerous, and there are safer alternatives
Contact Person: 
Michael P. Wilson, PhD, MPH
Contact Person's Email Address:
Labor Occupational Health Program, Center for Occupational and Environmental Health
Principal Investigators: 
Michael Wilson
Research Publications and Reports: 

"Confined Space Emergency Response: Assessing Employer and Fire Department Practices," Journal of Occupational and Environmental Hygiene, February 2012.

Website for Project or Program: 
Garrett Brown at Cal/OSHA, Bob Harrison at the Occupational Health Branch, California Department of Public Health
LA District Attorney Settlement Agreement, and the Center for Occupational and Environmental Health, UC Berkeley
Location - States: 
All U.S. states
Location - Countries: 
Publication Date: