Author(s): Guy Colonna. Published on March 1, 2012.

Confined spaces

Dangerous by Design

NFPA launches a new effort to spread the word on safe work practices for confined spaces—and to improve first responder tactics when things go wrong

NFPA Journal®, March/April 2012 

By Guy Colonna 

Every year, nearly 100 people across the country die in what are known as “confined spaces.” These are areas that can be dangerous because they possess limited means for entry and exit, have unfavorable natural ventilation that can contribute to the creation and buildup of atmospheric hazards, and are not intended for continuous human occupancy. Confined spaces span a wide range of industries and uses, including storage tanks, process vessels, hoppers, bins, silos, sewers, boilers, utility vaults, pipelines and pipe tunnels, and cargo spaces and holds on marine vessels. Steel mills, paper mills, chemical plants, refineries, public utilities, construction sites, recycling facilities, grain silos — they all contain confined spaces.

Such spaces are considered dangerous by design because they generally have limited or restricted openings for accessing and exiting, and they often contain products that can introduce atmospheric hazards. The hazards are more fully described in terms of atmospheric hazards, which include oxygen content, flammable gases or vapors, and toxic substances, and physical or mechanical hazards. These physical hazards can include engulfment, which can occur in grain storage bins or silos; entrapment, where the space design promotes an entrant becoming trapped due to narrow space configurations; and other examples such as slippery surfaces, noise, thermal stresses, or energized electrical or mechanical devices.


NFPA's Guy Colonna explains the formation and scope of the association's new project on Confined Space Safe Work Practices.

NFPA has many years’ experience addressing confined space situations and identifying effective solutions that ensure safe entry and work within confined and enclosed spaces in a variety of industry settings. With this track record in mind, NFPA’s Standards Council recently approved the formation of a new committee project to more directly address the ongoing problem of fire and life safety issues in confined spaces. According to the project’s scope, the Committee on Confined Space Safe Work Practices will have “primary responsibility for documents on safeguarding against fire, explosion, and health hazards associated with entry and work in confined and enclosed spaces. The committee shall also have primary responsibility for developing safe work practices based upon hazard recognition, evaluation, and control for those occupancies with confined or enclosed spaces. The safe work practices shall also address exit procedures from the spaces.”

The new committee’s work will focus on safe work practices, rather than necessarily establishing additional requirements, and will include translating existing regulatory language into practical approaches that can be understood and implemented at all levels of the affected workplaces. The committee will also look at responder safety issues related to confined spaces. 

Addressing gaps
An important task of the new committee will involve addressing gaps in coverage that have become apparent since the completion of a federal confined space regulation nearly 20 years ago.

In 1993, the Occupational Safety and Health Administration (OSHA) issued its long-awaited regulation addressing entry and work in confined spaces: “Permit-Required Confined Spaces (PRCS),” 29 CFR 1910.146. The regulation established a more concise definition for what constitutes a confined space: it must be large enough to permit entry to do work; it is recognized as not being intended for continuous human occupancy; and it has limited or restricted means of entry or exit. In addition, the agency used the presence of the hazards to determine what level of controls to implement. Permit-required and non-permit-required confined spaces were defined in terms of the presence of either the atmospheric hazards or physical mechanical hazards.



A Threat with Many Faces
Confined spaces exist in all sizes and shapes. The associated hazards — described as either atmospheric or physical/mechanical — pose serious danger when established safe practices are not followed.

The Basics
The responsibility of NFPA’s Committee on Confined Space Safe Work Practices will be to identify the basics of safe practices for entry, work, and exit, and then develop safe work practices applicable to specific workplaces.

The PRCS was long-awaited because, leading up to it, the National Institute for Occupational Safety and Health (NIOSH) had been citing lack of workplace safety standards as a contributing factor in the significant number of confined-space-related fatalities, observations that were collected in the 1994 report “Worker Deaths in Confined Spaces: A Summary of NIOSH Surveillance and Investigative Findings.” The NIOSH publication examined several key issues that OSHA had used to guide the development of its final regulation. First, atmospheric hazards contributed significantly to the fatality statistics from the mid-1970s to the late 1980s, which were generally dominated by oxygen deficiency. Second, regardless if the cause of the fatal incidents were attributed to atmospheric or physical/mechanical hazards, attempted rescue also increased the number of workers who lost their lives in confined spaces. OSHA estimated that for the 1979–1981 period, confined spaces were the cause of 174 fatalities per year.

The confined space problem has improved in the nearly two decades since OSHA’s PRCS was issued — but only to a point. The Bureau of Labor Statistics (BLS) Census of Fatal Occupational Injuries provides a source for data on confined space fatalities resulting from both atmospheric and physical hazards. BLS analysis of its data for the five-year period from 1997–2001 indicated that the average number of fatalities was 92 per year. A similar review of the most recent five-year period that BLS data are available, from 2005–2009, shows the rate for fatal incidents to be virtually unchanged — about 92 per year, or the equivalent of an incident every four days.

One relevant change in the data, however, is that 20 years ago the focus was on atmospheric hazards, as they often represented as much as two-thirds of the reported incidents, according to NIOSH. The most recent data suggest that the relationship has flipped: physical hazards accounted for approximately 60 percent of the reported incidents, while atmospheric hazards accounted for about 33 percent. It’s not yet clear what factors have contributed to this shift, but it’s possible that the increased incidents involving entrapments at grain storage facilities (see “A Threat with Many Faces.”) are responsible for at least some of it.

NFPA’s work in the area of confined spaces is represented by its long history guiding the safe entry and work practices for the maritime sector. NFPA’s involvement can be traced to the 1920s and involves maritime construction and repair — typically hot work. Since 1922, NFPA has developed and published NFPA 306, Control of Gas Hazards on Vessels, which defines the safety conditions that must be met in order for workers to enter the various maritime vessel confined spaces and to perform hot work associated with construction, repair, or scrapping (also referred to as shipbreaking). Because of the flammable and combustible liquids and gaseous cargoes and fuels carried aboard these vessels, any hot work activity planned for the tanks, piping, or adjacent spaces must be prepared according to the NFPA standard, which has been adopted by OSHA and U.S. Coast Guard regulations.

In the mid-1980s, NFPA codes and standards expanded to address a land-based application involving confined spaces and hot work when it developed a new standard to address activities associated with the removal of underground petroleum storage tanks identified as leaking through inspections conducted in response to an Environmental Protection Agency (EPA) initiative. NFPA 326, Safeguarding of Tanks and Containers for Entry, Cleaning, or Repair, used a model followed within the maritime segment that stresses a three-step approach to safety when preparing to enter and work in confined spaces: hazard recognition, hazard evaluation, and hazard control.

An important aspect of the maritime standard is the presence of a specifically identified and designated individual, the Marine Chemist, who is certificated and charged with implementing the three-step hazard program for all maritime spaces. The Marine Chemist is required by OSHA and Coast Guard regulations to evaluate the hazards associated with entry and work in maritime confined spaces before such work can proceed. The Marine Chemist, certificated through an industry supported and established program managed by NFPA staff, documents compliance with federal regulations and NFPA 306 and issues a permit stating the conditions found and the entry and work limitations that apply to each inspection. No such uniquely qualified individual exists within other industrial sectors to implement the regulations of OSHA or other safe work practices involving confined spaces.

NFPA also developed and maintains confined space technical rescue provisions that complement OSHA’s PRCS requirements. These provisions are found in NFPA 1670, Operations and Training for Technical Search and Rescue Incidents, and NFPA 1006, Technical Rescuer Professional Qualifications. A significant element of OSHA’s regulation was the requirement for employers to provide a confined space rescue capability for all entries meeting the “permit required” classification. Employers are permitted to satisfy this requirement either by providing an on-site rescue capability or by relying on off-site services, which generally means the local fire department. In the months following OSHA’s issuance of the PRCS, there were a number of instances involving rescue attempts by ill-prepared local fire departments that resulted in loss of firefighter lives. Guidance in the form of NFPA 1670 and the companion professional qualifications document, NFPA 1006, have subsequently addressed much of the early training needs for those involved with emergency response to confined space workplaces.

Even so, as recently as 2010, firefighter lives continued to be lost or threatened while responding to these emergencies. In June of that year, following two separate confined-space incidents that killed the initial civilian victims and critically injured several firefighters, major firefighting organizations, including the International Association of Fire Chiefs, called for fire chiefs and officers to issue stand down orders in their departments, meaning that personnel would postpone any non-emergency tasks to focus on confined-space safety training.

Just weeks after the stand down call, however, a volunteer firefighter in New York State died while attempting to rescue a utility worker who had entered a manhole to investigate a reported sewer problem; the medical examiner reported that the cause of death for both men was asphyxia due to low oxygen and exposure to sewer gases. A NIOSH report on the incident listed contributing factors in the firefighter’s death as unrecognized hazards involved with a confined space; lack of standard operating procedures for confined space technical rescue operations; and an ineffective incident management system for a confined space technical rescue operation. The agency’s key recommendations included ensuring that firefighters are properly trained and equipped to recognize the hazards of, and participate in, a confined space technical rescue operation; that standard operating procedures regarding technical rescue capabilities are in place and a risk benefit analysis is performed to protect the safety of all responders; that an effective incident management system is in place that supports technical rescue confined space operations; and that a safety officer properly trained in the technical rescue field being performed is on scene and integrated into the command structure.

Safety in any workplace
While the OSHA PRCS standard provides the basic requirements for hazard identification and classification and hazard evaluation, NFPA recognizes that more can be done to address confined space issues. With a few exceptions — such as specifications requiring a permit system, and for emergency services and confined space rescue — the PRCS does not effectively incorporate other control measures such as isolation, substitution, ventilation, and personal protective equipment into safe work practices. In fact, the requirements seem to emphasize the rescue provisions over those associated with prevention of the need for an emergency rescue.

Recognizing that the minimum requirements of the federal standard still fall short when interpreted and applied at workplaces throughout many industries, NFPA’s new project will focus on developing safe work practices suitable for a variety of workplaces. The committee will soon begin work on developing a document and, considering the nature of the safe work practices, it is likely that the document would be best suited as a guide or recommended practice. In addition to considering factors related to entry, work, and exit, the final document could include information applicable to the individual who performs the testing of the atmosphere in these spaces. NFPA 306 and the maritime program have been in place for 90 years and represent one extreme: the program requires and relies on the testing to be conducted by a certificated professional, practicing to a state-of-the-art industry standard of best practices. Nothing similar exists anywhere else in industry, but as a guide or recommended practice, the attributes of a Marine Chemist-like person could be presented for use as the model since so much depends upon effective atmospheric monitoring in these spaces.

This important new project offers an opportunity to interpret the requirements found in the OSHA regulation and other standards and to guide the implementation — in other words, to turn “What do I have to do?” into “Here’s how I can do it.” The regular occurrence of confined space incidents demonstrates the need for continued vigilance toward this workplace hazard, one that demands consistent attention to recognize, evaluate, and control so that workers can be assured of safe entry, work, and exit from all spaces.

Guy Colonna is head of NFPA’s Industrial and Chemical Engineering Division.


A Threat with Many Faces

The following examples highlight some common aspects associated with confined spaces and the incidents that can occur in these workplaces. Confined spaces exist in all sizes and shapes and are found throughout many industries. The associated hazards — described as either atmospheric or physical/mechanical — pose serious danger when established safe practices are not followed. And where multiple fatalities result, would-be rescuers continue to contribute to the lives lost.

Grain bins
Rescuers at the scene of a grain bin incident in Illinois in 2010 that killed two teenage workers. (Photograph: AP/Wide World)
  • Grain storage bin, Illinois, 2010
    Two teenage workers lost their lives and another worker was seriously injured when they were engulfed by corn inside a grain bin. The incident occurred as the workers were “walking down” the corn inside the bin to make it flow more effectively as part of the process of emptying the bin.

    An annual report published by Purdue University in November 2010 documents that the number of similar grain-storage entrapment incidents nationwide increased significantly during the first 10 months of 2010, pushing the number to a record high. Through October 2010, the Purdue report indicated that 46 grain entrapments occurred, with 25 fatalities. Acknowledging the trend, OSHA Assistant Secretary Dr. David Michaels sent a letter to grain storage facility operators reinforcing the well-known and long-recognized hazards associated with entry into grain storage bins and silos. In addition, OSHA issued an alert, “Dangers of Engulfment and Suffocation in Grain Bins,” reminding facility operators and workers of the safety procedures contained in the grain industry’s standard, 29 CFR 1910.272(g).
  • Waste recycling facility, Texas, July 2009
    An employee cleaning a tank that had held some kind, or mixture, of flammable liquids was killed in an explosion when an altered piece of equipment ignited flammable vapors inside the tank. The fatality was the third death in less than a year at this employer’s facilities; two hydrogen sulfide exposure-related deaths occurred in December 2008 and April 2009 at other facilities also located in Texas. OSHA issued citations alleging the use of unsafe electrical equipment in the tank wash area due to the presence of flammable and combustible vapors. Additional OSHA citations alleged that the employer failed to ventilate tanks in which employees were working, exposing them to toxic atmospheric hazards. An additional series of citations alleged failure to implement confined space rescue procedures.
  • Recycling facility, New York, June 2009
    Three people died when a worker fell unconscious after exposure to hydrogen sulfide while cleaning a dry well, an underground structure that disposes of unwanted water, typically storm-water runoff. In an all-too-common scenario, the two additional victims were would-be rescuers. According to published reports, one was the owner of the recycling company, and the other was the first victim’s father.


The Basics
A roadmap for NFPA’s new committee on confined spaces

As envisioned by staff, the responsibility of NFPA’s Committee on Confined Space Safe Work Practices will be to identify the basics of safe practices for entry, work, and exit, and then develop safe work practices applicable to specific workplaces or occupancies. The individual work practices can be specific to industry, space types and design, or to work activity, such as hot work repairs, tank cleaning, or coating and painting. The entry, work, and exit concept provides a simplified outline that can be applied to each work practice.

Confined spaces
Firefighters get confined-space training in an industrial setting. (Photo: Wilbraham (Mass.) Fire Department)

This involves the hazard recognition step (identify and classify the spaces and the hazards, whether they’re atmospheric or physical/mechanical); the hazard evaluation step (gathering hazard property information and performing atmospheric monitoring for oxygen, flammability, and toxicity); and the hazard control step (ventilation, isolation — including lock-out/tag-out — substitution, permits, warning signs, frequent testing, and personal protective equipment as needed).

The work aspect of safe work practices involves follow-up as necessary to maintain the safe conditions established for initial entry. This utilizes some of the same processes as the steps in the entry phase, but now the hazard identification must also examine new hazards that occur or are introduced as a result of the work, such as spray painting, solvent degreasing, or hot work. Accident data demonstrate that programs for confined space entry and work often overlook the fact that the work will significantly impact the original safe conditions; this step focuses attention on that fact and makes it essential that measures be taken as necessary.

The U.S. Chemical Safety Board highlighted the importance of integrating the work into confined space safe work practices with the publication of its 2010 safety bulletin on hot work performed in and around tanks. The report cited 60 fatalities that have occurred since 1990 due to hot work activities in or on tanks. Best practices for mechanically ventilating spaces, a weak point for many confined space safety programs, would also be addressed. Ventilation must address the health and personnel exposure aspects of the atmosphere, as well as flammability, since many of the operations involve flammable and combustible materials.

This incorporates the need for rescue provisions, and may also influence best practices by focusing on the importance of adequate access and egress. Many confined space problems arise from the size, number, and placement of access/egress points to and from confined and enclosed spaces. The committee could introduce concepts related to designing new confined spaces with safety in mind by, for example, making it easier to mechanically ventilate the spaces or by enlarging the openings into and out of the space. The focus on exit in this third element also benefits from NFPA’s confined space rescue expertise gained from the work within the NFPA 1670 and NFPA 1006 projects.