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31 Posts authored by: nancypearce Employee

The Technical Committee on Confined Space Safe Work

Practices put some “finishing touches” on the preliminary draft of a new confined

spaces guide at a meeting in Charlotte NC last week.   This best practices guide, written for all

types of confined space entries, will complement other confined space

regulations and standards and will provide more prescriptive guidance to

address some of the gaps in existing confined space documents. For example, the

guide provides detailed information on the selection and use of atmospheric

monitoring devices and ventilation.  It

also outlines qualifications and competencies for those involved in confined

space entry and rescue.  


The preliminary draft of the best practices guide will be

submitted to the Standards Council for review at their July meeting.   Once approved, the preliminary draft will be

posted to the document information page<a>.   The public and stakeholders can then submit public
input on line to help the committee determine what additions, changes and
enhancements should be made to the document. 
You can sign up for “email alerts” located above the tabs on the
document information page to be notified when the draft has been posted.

The work of the committee is far from over!   This has been a tremendous undertaking for a
relatively short period of time.  The
Committee is asking the public, stakeholders and potential users of the
document to assist them in completing their work by providing input to make this
a document that can really improve confined space entry safety.   The Committee will carefully consider all
public inputs when they gather again for the official First Draft meeting in

We look forward to

hearing from you as this project moves forward.&#0160;

If you have questions please contact me at .

In 1984 a rescuer was killed when an explosion occurred while he and his coworkers were attempting to cut a hole in a toluene tank to retrieve a worker who had died entering the confined space.  The accident, captured on video, provides a graphic view of the hazards of performing hot work around confined spaces. 

This incident was not unique.  Fatalities from welding and hot work are often are associated with confined spaces and the areas adjacent to these confined spaces .  The CSB has identified over 60 fatalities since 1990 due to explosions and fires from hot work activities on tanks, which are, of course, confined spaces.  The CSB defines hot work as “work involving burning, welding, or a similar operation that is capable of initiating fires or explosions. Hot work also includes other activities with the potential to create a source of ignition such as cutting, brazing, grinding, and soldering.”  CSB has released a Hot Work Safety Bulletinthat describes 11 incidents and has concluded that a critical factor in many of the accidents was the lack of continuous gas monitoring prior to or during the hot work activities.   CSB noted that in many of the incidents there was inadequate monitoring not only in the confined spaces but also in the spaces adjacent to the confined space.

 There are many organizations that have developed welding safety information.  Each deals with a particular type of industry or specific work to be performed.  For example, The National Fire Protection Association (NFPA) has several standards related to welding including NFPA 51B  Standard for Fire Prevention during Welding, Cutting and Other Hot Work, NFPA 306 for the Control of Gas Hazards on Vessels (for the marine industry), and 326 Standard for the Safeguarding of Tanks and Containers for Entry, Cleaning and Repair .   The American Welding Society (AWS) publishes a standard, AWS Z49.1 Safety In Welding and Cutting and Allied Processes, as well as numerous fact sheets and welding safety information.   The American Petroleum Institute (API) has numerous standards related to welding on petroleum tanks including  API 653 Tank Inspection, Repair, Alteration, and Reconstruction,  API RP 2009 Safe Welding and Cutting Practices in Refineries, Gasoline Plants, and Petrochemicals Plants and  API Std 2015 Safe Entry and Cleaning of Petroleum Storage Tanks, Planning and Managing Tank Entry From Decommissioning Through Recommissioning.  API also publishes a number of other standards for specific processes that may involve welding or other hot work.    And Federal OSHA has several welding standards and has a health and safety topic page dedicated specifically to welding.

The inherent hazards associated with welding are complicated when welding is done in or around a confined space.  The information available on welding safety is vast, but the connection between welding hazards and confined spaces must be made in order to decrease injuries and fatalities that occur from hot work. 

http://www.nfpa.orgTypically we think of climbing down into tanks, vaults or manholes for confined space entries.  Most would not think of wind turbines as having confined spaces. 

Large enough to enter and perform work, restricted means of entry or egress and not designed for continuous human occupancy…. Wind turbines clearly have components that meet the definition of a confined space AND they have potential hazards. 

With the push towards green energy, wind turbine installations are increasing rapidly.  In 2012 wind energy became the number one new energy source, with over 45,000 wind turbine installations currently in the U.S., according to AWEA (American Wind Energy Association).    


While green technology may be good for the environment, it is not without hazards to the workers who install and maintain the technology.   As OSHA indicates on their Green Job Hazards webpage, “Green jobs are not necessarily safe jobs”.

Hazards for workers in wind turbines include falls, electrical, mechanical, fire, and confined space hazards. Both OSHA and AWEA have pointed out the need for confined space training of wind turbine workers.   Confined spaces exist during construction and after installation of the turbines.  There are four main components that may be considered confined spaces; the tower (vertical support), the nacelle (the housing that contains the electrical components) the hub (hub attaches to nacelle) and the blades (attach to hub).  During construction of the turbine workers may need to enter sections of the tower, nacelle, hub or blades to finish seams, grind, paint, etc.    When fully installed, workers need to climb up the tower to reach the narrow, restricted spaces of the nacelle, hub and blades for maintenance, inspection and repairs.  Electrical hazards have been the source of a number of fatalities and fires in wind turbines within the confined spaces.   An electrical incident or spark that occurs in the nacelle can quickly engulf a worker whose only way to exit the space is to descend a several hundred foot ladder or to climb on the roof of the nacelle. Some nacelles are made with polystyrene type foam which is extremely flammable and adds to the fire risk.  Nitrogen used in the accumulator, off-gassing of construction materials, poor ventilation and sources such as decomposing birds or rodents, can create a hazardous atmosphere.  And if something goes wrong inside a wind turbine, the challenges to rescue are significant.     

The National Fire Protection Association is developing a Best Practices Document for confined space entry. This document will address gaps in existing standards and will be more prescriptive in describing things like how to identify potentially toxic atmospheres and select the proper gas monitor for entry and how to include the evaluation of adjacent spaces into your confined space entry program.    This is a document that is looking to go beyond the minimum standards and will provide those looking to develop a “gold star” confined space entry program with the information they need to do so.  Please email me at for further information and/or leave a comment below for discussion.  I look forward to hearing from you!

I used to (naively) believe that training was the only way to prevent workplace injuries and fatalities.  If I did a great job training workers on the hazards of a particular task and demonstrating and explaining how they could eliminate the risk of injury or fatality, I believed they would follow my advice.

However, after more than 25 years experience, I now understand that while training is important, it is not the complete panacea I was hoping for.   I could provide a great training session and get lots of positive feedback from those participating, only to observe unsafe procedures and unsafe work practices by these same employees several weeks or months later.  So more recently, I have been rethinking the chemistry/engineering aspect of worker safety and have been thinking that if I really wanted to impact worker health and safety, that perhaps  I should go back to school for a behavioral psychology degree!  I have come to realize that technical information and training alone does not prevent workers from taking risks. 

So imagine my excitement when I read an article recently on breaking the chain of fatalities and near misses in the “would-be rescuers” in confined space entry.   The article addresses the psychology behind those who rush in to confined spaces to rescue victims even after being trained not to do so.   The article is written by another confined space trainer who is apparently equally interested in figuring out the psychology behind the phenomenon of such risk takers.   The article in the American Industrial Hygiene Association (AIHA) journal the Synergistprovides references to several fascinating articles written by psychologists on how humans may be "hard wired" to be altruistic.  The articles indicate that humans derive pleasure from "heroic" acts that they perceive show compassion and empathy.   

So what do we do with this information?  The author recommends that as trainers we may need to point out and discuss the human behavior aspect to our students, explaining that this “impulse” may occur at the time of an emergency.  The student will have to remember that they are fighting a natural human response when the urge to rush in and save the individual who is down in the confined space kicks in.   The author also recommends reminding the student that the act of rushing in not only could make him/her the next victim, but it also may rob the current victim of an opportunity for a viable rescue.   

I encourage you to read the article!   If you have any other thoughts on how to prevent the “would-be rescuer” from jumping into a confined space I would love to hear your suggestions!  

The National Fire Protection Association is developing a Best Practices Document confined space entry. This document will address gaps in existing standards and will be more prescriptive in describing things like how to identify potentially toxic atmospheres and select the proper gas monitor for entry and how to include the evaluation of adjacent spaces into your confined space entry program.    This is a document that is looking to go beyond the minimum standards and will provide those looking to develop a “gold star” confined space entry program with the information they need to do so.  Please email me at for further information and/or leave a comment below for discussion.  I look forward to hearing from you!

Gas monitoring with proper equipment is probably the number one most important step you can take to protect against confined space fatalities. But selecting the right gas monitor for entry is not without its challenges.   Gas monitoring for confined space entry can be straightforward or it can be complicated, depending on the type of space being entered and the work that will be performed.  All gas monitoring for confined space entry must include tests for both oxygen (%) and flammables (% LEL).   Beyond these two tests, it is up to the employer to determine what other toxic gas monitoring needs be done.    A typical four gas meter will include carbon monoxide and hydrogen sulfide as the additional toxic gases.  But confined space entry is not a “one size fits all” type of operation.  If you simply use the “standard” four gas meter, and do not carefully consider the need for monitoring other potentially toxic gases that may be present, you may not obtain the results you need to determine if the space is safe for entry.  The error could lead to catastrophic results.

All toxic gases that are likely to be in the space should be identified prior to entry.  But determining what these toxic gases may be requires some detective work.  Not only do you need to know what was in the space previously, but you also need to know what toxic gases may be of concern as a result of the work that will be done in the space.   Reactions between materials and byproducts further complicates the identification. If there is decaying material in the bottom of the tank, you may need to evaluate byproducts of the decay such as hydrogen sulfide.  If there were chemicals previously stored in the tank, the vapors may not be released initially, however residual vapor pockets in the bottom of the tank may release trapped vapors when stirred up during entry or cleaning.   Work such as welding on stainless steel can lead to exposures to hexavalent chromium and nickel, both carcinogenic agents.  All potential sources of atmospheric hazards must be considered and then evaluated using a careful selected monitoring device.   

If available, Material Safety Data Sheets (MSDSs or SDSs) on products previously stored in a confined space can provide useful information on toxicity, flammability, reactivity and decomposition products.   Material Safety Data Sheets can also be reviewed for all materials that will be brought INTO the space such as cleaning chemicals or welding gases. Chemical ingredients that are listed on the MSDS and have OSHA or other recognized exposure limits must be tested and compared to these limits.  Direct reading sensors that can be incorporated into the gas monitor may not be commercially available for all contaminants that you need to evaluate.   Other test methods such as photoionization detectors or colorimetric detector tubes may be needed to screen for the presence of these toxic materials.   Photoionization detectors can provide generic information on the presence of volatile organic compounds (VOCs) however they can only be used as a sort of screening tool for the presence of VOCs unless you know exactly what contaminant you are measuring.    Detector tubes that change color in proportion to the air contaminant concentration can also be used.  Detector tubes are not particularly accurate (+/-25 % error is typical) but can provide some initial screening for the presence of a particular toxic material and an estimate of the amount present. 

A comprehensive identification of the toxic materials expected to be present in a confined space, and then selection of the proper gas monitor by a qualified individual, is necessary to insure that the proper atmospheric tests have been done prior to and during entry.  However, there are some contaminants that cannot be easily evaluated by gas monitoring of any type.   Properly placed continuous ventilation can provide dilution of all contaminants within a confined space.  It is critical that entrants are always attached to non-entry rescue equipment and are wearing breathing air while entering a confined space where there may be unknown or “unmeasured” toxic atmospheres.  

The National Fire Protection Association is developing aBest Practices document for confined space entry. This document will address gaps in existing standards and will be more prescriptive in describing things like how to identify potentially toxic atmospheres and select the proper gas monitor for entry.    This is a document that is looking to go beyond the minimum standards and will provide those looking to develop a “gold star” confined space entry program with the information they need to do so.  If you have any suggestions for what you would like to see in this type of document related to gas monitoring or other issues you think should be included in a best practices document,  please email me at and/or leave a comment below for discussion.  I look forward to hearing from you!

About once a month I scan the web to see if there have been

any confined space fatalities.&#0160;

Tragically, I almost always find one, and it is not unusual to find

several fatal confined space incidents. Even worse, there are times I find multiple fatalities in a single confined space


The fatal confined space accident I found this month was
particularly disturbing to me. It seemed so blatantly obvious that the space
and work being performed would require at least some basic confined space entry
procedures, yet none appear to have been followed. 

A company that cleans industrial tanks was hired to clean
the bottom of a 40 x 50 foot 6000 gallon tank that previously contained the
highly toxic solvent, methylene chloride.  
It appears that he “fell” into the tank, and was found unconscious at
the bottom.  The 15 towns responding to
the incident with fire/hazmat/rescue personnel, very quickly realized after
testing the tank’s atmosphere that the 12% oxygen level meant that this would
be a body recovery and not a rescue. 
They then proceeded to take the necessary precautions to protect rescue
workers from suffering the same fate as the 37 year old worker. 


While this fatality is still under investigation by OSHA it

is clear that there were some major problems with this confined space

entry.&#0160; It appears that not just some,

but ALL of the basic confined space entry procedures were ignored.&#0160; If even ONE of the basic confined space entry

procedures had been followed this worker may be alive today.&#0160;&#0160; It appears that no gas monitoring was

performed prior to entry. &#0160;&#0160;If it had

been, the oxygen alarm would have sounded indicating that the atmosphere

required ventilation prior to entry.&#0160;&#0160; If the atmosphere had not been tested, even if the worker had been attached to a

tripod, harness, winch rescue system, he likely would not have fallen or if he

did, his coworker could have pulled him out.&#0160;&#0160;

And sadly, it appears that the worker was not wearing the proper PPE for entry.&#0160;&#0160; A half-mask air purifying respirator was

found near his body.&#0160; Air purifying cartridge

respirators do NOT protect against methylene chloride exposure and NO air

purifying respirator protects against an oxygen deficient environment.&#0160; If the worker did need to enter the tank to clean the residue while the atmosphere was still unsafe, he would have needed to wear a self contained breathing apparatus or an airline respirator with an auxilary self contained breathing supply.&#0160; Further information on the fatal accident can

be found on the web.&#0160;

The question I have is why would an experienced industrial
cleaning company worker have entered this tank without a confined space permit,
air monitoring, ventilation and non entry rescue capability?  Something just does not seem right.  An industrial tank cleaner (and certainly his
employer) should have recognized this was a confined space and should followed
at least some basic confined space procedures. The company website discusses confined space as one of their specialties so this was not a company that was unaware of the hazards of this type of work.   

The medical examiner has now reported that
the worker died of head trauma from the fall.  
 I have to wonder if perhaps the
worker was overcome by methylene chloride vapors in the space ADJACENT to the
tank opening and if he fell into the tank before he had a chance to assess the
hazards and to follow some basic permit required confined space
procedures.  The worker’s partner never
entered the tank but was also taken to the hospital with symptoms, leading me
to believe that he was exposed to  methylene chloride vapors in the adjacent
space outside the tank opening.  The Agency for Toxic Substances and Disease Registry (ASTDR) lists methylene chloride as a material that causes dizziness and unsteadiness. [ ASTDR |]indicates that even at low levels of exposure, workers may become less attentive and less accurate at tasks requiring hand eye coordination.  

Unfortunately hazards of adjacent spaces are not generally
recognized and are not covered in OSHA’s permit required confined space entry
standard.  The Chemical Safety Board has noted
the hazards of adjacent spaces in some of their investigations, including the
Valero Case
, and has encouraged NFPA to address adjacent spaces in their Best
Practices Document currently in development.  

The NFPA Technical Committee on Confined Spaces is working
on the development of a best practices document on confined space entry
designed to address gaps in existing confined space standards.   This document will go beyond the regulatory
requirements and provide more prescriptive guidance on how to safely enter,
work and exit from a confined space.  The
recognition and control of adjacent space hazards will be included in this
document.  Do you have any thoughts on
how to address adjacent space hazards or other ideas for what should be
included in the document?  If so please
leave a comment or contact npearce@ 


OSHA has recently issued citations for yet another fatality that occurred  adjacent to a confined space. As discussed in a previous blog, the hazards of adjacent spaces are not often recognized by employers and are not specifically addressed in the OSHA Permit Required Confined Space standard (1910.146)

North Carolina Dept of Labor recently cited Smithfield Packing ~ $250,000 for a fatality that occurred when a worker was overcome by hydrogen sulfide gas while filling a tanker with liquid sludge.   The atmosphere outside the tank was not tested prior to or during the filling and since the worker never ENTERED the tank, there were no confined space entry procedures set in place.   There was no permit, no attendant, not testing. See story.

The existing OSHA 1910.146 Permit Required Confined Space Standard for general industry does not address hazards immediately outside and adjacent to confined spaces.   Atmospheric hazards adjacent to a confined space can create both health and safety hazards.  Workers can die as a result of breathing in toxic materials released into the adjacent space or as a result of a fire and explosion caused by flammable vapors leaking into the adjacent space.  

How should we address those hazards that are not necessarily inside the confined space but are associated with the confined space hazard?    In the marine industry, both the OSHA Shipyard standards (1915.14) and NFPA 306 for the Control of Gas Hazards on Vessels recognize the hazards of adjacent spaces.   Both standards require that a Marine Chemist evaluate not only the confined space but also the area adjacent to those spaces whenever hot work such as welding will take place.

    NFPA is developing a best practices document for confined space entry.  The new document will likely include the evaluation of hazards in the area adjacent to the confined spaces.   We would love to hear your ideas for how to address adjacent space hazards in the new document!

It is generally recognized that lack of oxygen is the leading cause of death in confined spaces.&#0160; You cannot see or smell a oxygen deficiency therefore the hazard is not readily apparent to someone entering an oxygen deficient environment.&#0160; The only way to determine if a confined space has sufficient oxygen is to test the atmosphere with a calibrated gas monitor.

The air we breathe contains
approximately 20.9 % oxygen.   Most of
the remaining 79% is made up of nitrogen with smaller quantities other gases
such as argon and carbon dioxide.   Interestingly,
contrary to what most people think, the percentage of oxygen in the air remains
the same even at higher elevations.   
However because the air at higher elevations is less “dense”, there are fewer
molecules of everything present, including oxygen.  Less oxygen molecules means it is it
potentially harder to breathe despite the fact that a gas monitor will still
read 20.9%.

Low levels of oxygen can lead to impaired judgment, lack of
coordination, behavior changes, dizziness, fatigue and ultimately collapse and
death.   Sometimes workers think they can
“hold their breath” for a second to enter a space quickly without testing or
ventilation.  But even one breath of
oxygen deficient air could prevent your muscles from responding so that you
cannot have the strength to escape the space even if conscious.  Those with coronary, pulmonary, or
circulatory disease may feel symptoms before others.   I once investigated a confined space
incident in which only one of three workers was dizzy and passed out.  The atmosphere was later tested and found to
have a slightly lower oxygen level of approximately 18-19.5 %.  The only worker affected was the one who had
a pre-existing cardiac condition.  

Low oxygen levels occur from chemical or biological processes
or reactions that either consume or displace oxygen from the confined
space.  Common causes of oxygen
deficiency include:

    • Rusting-(rusting is an oxidation process that consumes

    • Combustion-(all sources of combustion such as propane
      heaters, welding, consume oxygen).

    • Displacement by other gases- (such as Nitrogen purging,
      inerting, welding gases)

    • Decomposition of Organic Matter (Micro-organisms
      consume oxygen and produce flammable methane gas that can also displace oxygen

 While most gas
monitors will not alarm until 19.5% (OSHA allowable lower limit for entry), it
is recommended that you establish a policy to require 20.9 % oxygen prior to
entry.   If you test the atmosphere in a confined space
and it is anything OTHER THAN 20.9% you should investigate the source of this
oxygen deficiency and ventilate the space prior to entry, retesting until the
oxygen level is maintained at 20.9%.  With
so many variables and potential hazards in confined spaces, you should strive
to maintain the atmosphere as close to “normal” as possible.  


NFPA is in the process of developing a Best Practices Document for Confined Space Entry.&#0160; One item that we will likely include as a best practice is to prohibit entry into confined spaces where oxygen levels are less than 20.9% and to ventilate the space until the levels reach 20.9%.&#0160;&#0160; You may wish to sign up for the alerts for the document that is being developed by going to and clicking on the SIGN UP FOR EMAIL ALERTS link above the tabs. An email will be sent notifying you of any meetings or additions to the document information page related to the confined space document. If you have ideas for what should be included in this document or would like to be involved in document development please let us know!&#0160; Task groups to develop draft chapters of the document are now being formed.&#0160; If you have an interest or special expertise in a particular area let us know how to contact you!


How do you demonstrate hazardous atmospheres to trainees?  A training video can only go so far to demonstrate this principle.   I once read an article that contained a “recipe” for setting up an excellent training prop that I have now used in training for many years.  It provides a very visual example of how an apparently benign looking enclosure such as a water tank or valve vault can actually be deadly.

Take a large office water cooler size empty water bottle.  How bad could a water bottle be after all?   Add a handful of leaves, tiny bit of dirt or some mulch, along with a couple of iron nails or springs or rebar.  Add a bit of water to wet everything and then cap the bottle.  Let it sit for several months, preferably in a warm location.   Looks fairly innocuous right?   Looks like a typical meter pit or vault.   Other than a tiny bit of decaying material in the bottom of the tank, the container looks safe but it may not be.  

Use a calibrated four gas meter to test this bottle after a few months.  You will likely find that the atmosphere is oxygen deficient and the LEL meter will indicate that there is a potentially explosive environment, most likely due to the methane formation.  You can recap this bottle and continue using it for future demonstrations. You may need to “recharge” the bottle periodically with more materials and water and cap it for a couple months between trainings.  

Many confined spaces contain all the same ingredients shown in the demonstration-metal ladders and equipment, dirt or debris and water.  I have found this demonstration to be an effective means to show training classes why they need to monitor all confined spaces, even if they did not previously contain chemicals. 

Do you have demonstrations or training ideas that you would be willing to share?  NFPA is working on development of a Best Practices Guide to Confined Spaces.   If you have any training ideas or other information that you would like to see included in the new document please let us know!    

Confined spaces can visually look completely safe but as we know, often they are not.  Historically, atmospheric hazards have been the leading cause of deaths in confined spaces.  In order to assess atmospheric hazards, both visual inspections and atmospheric testing of confined spaces must be done.   There is often more than meets the eye!

When you look at a confined space, you must ASSUME that it could have a hazardous atmosphere until you verify that it is safe with a properly selected and calibrated gas monitor.  But while it may be quite clear that there is a need to test a tank that contained chemicals previously, it may NOT be so clear that you need to test a space that looks fairly innocuous such as a valve or meter pit that never contained a chemical.  Yet these spaces have the potential for hazardous atmospheres from numerous sources. Contaminants can enter confined spaces located below grade through walls and floors from leaking underground gas and fuel lines even a mile away.  Decaying vegetation and debris in vaults and pits can create flammable methane and toxic hydrogen sulfide. 

And what if the tank only contained water previously?  How bad could it be? Water tanks may be rusty.  The rusting process uses up oxygen and that may lead to an oxygen deficient environment.  What about a brand new concrete vault?  Concrete can use up oxygen as it cures and can in some situations may create an oxygen deficient environment.   So even a brand new concrete vault may contain a hazardous environment.  Is nothing safe??

You may now be convinced of the importance of testing the atmosphere regardless of how benign the confined space.  But wait, there is more…. 

Testing the atmosphere is only one step in assessing atmospheric hazards.   Visual inspections are important because small pools of liquids or debris lying stagnant in the bottom of a tank may not necessarily be vaporizing at a level to register on a gas monitor.  However after the space is opened and heat, ventilation or a worker walking around in or cleaning up the liquid changes the atmosphere, this liquid may to begin to vaporize and create a hazardous atmosphere.  It does not take a lot of liquid that is vaporizing in the bottom of a tank to reach dangerous atmospheric levels.  Decaying debris in the bottom of a confined space may contain pockets of gases that are released when workers stir up the debris when inside the tank to perform work or cleaning. So the gas monitor reading is critical but may provide a false sense of security unless visual inspection is also part of the assessment. 

NFPA is in the process of developing a Best Practices document for confined space entry.  If you have ideas for what should be included in this document or would like to be involved in document development please let us know!  Task groups to develop draft chapters of the document are now being formed.  If you have an interest or special expertise in a particular area and would like to work with a task group let us know how to contact you!

Because confined spaces are not designed for human occupancy they have hazards that are not typically found in locations that ARE designed for occupancy.  So what about the person who has to enter those spaces to perform work?   Confined spaces are usually not well ventilated and may have unguarded equipment that would not be expected to be found in occupied areas.   They may have inwardly converging walls or convoluted piping that could lead to entrapment.  Once you have identified your confined spaces, the first step prior to entry is to determine the potential hazards that may exist in those spaces.  Hazard Identification is one of the most critical components of a confined space safety program.  If a hazard is not identified, then it cannot be eliminated or controlled!  That omission could lead to a fatality.     

Confined space hazards can generally be placed in two categories-atmospheric and physical hazards. Atmospheric hazards fall into four general categories-toxic, oxygen deficient, oxygen enriched and flammable environments.  Atmospheric hazards are invisible. The air in confined spaces looks and often smells just like the outside air, so workers entering the space may not recognize that the atmosphere is dangerous. A well chosen, calibrated gas monitor used to properly monitor the air is the way to insure the atmosphere is safe and that there is sufficient oxygen for breathing. The atmosphere in a confined space may also lead to explosions or fires.  Gas monitors check for flammable atmospheres and for oxygen enriched atmospheres that can increase the risk for and intensity of a fire. 

 In addition to gas monitoring, it is critical that a visual inspection is conducted to look for potential residues and other hazards in the confined space that may not be detected on the gas monitor.  It is important to review the list of chemicals that may have been stored or used in the space previously.  Furthermore, there must be a determination of potential atmospheric hazards that will be brought INTO the space or may be created by the work being done in the space.  Atmospheric testing may show a safe environment prior to entry, but fumes and combustion by-products will be of concern if welding is to be performed in the space. Cleanup of debris in the bottom of the tank could stir up toxins and hazards that may not show up on the gas monitor when the debris is untouched prior to entry. The evaluation of hazards must include what exists before entry as well as what hazards may occur while the worker is inside the space.   

Safety hazards in confined spaces include entrapment and engulfment as well as physical hazards caused by mechanical or electrical equipment.  The configuration of a tank with inwardly converging walls could lead to entrapment of a worker.  Solid materials such as grains or sand can lead to engulfment.  Liquids inside a space could lead to drowning.  It is critical that the hazard assessment determine if there are process related lines that enter the space.  These will need to be isolated from the space prior to entry.   A determination must be made to see if there are rotating parts, exposed electrical, hydraulics or other energy sources that will need to be eliminated or controlled prior to entry.   A Lockout/Tagout program typically goes hand in hand with a confined space entry program. See OSHA 1910.147 

There are numerous other health and safety hazards that are also common for confined spaces including noise and heat, cold extremes, slips and falls that should also be included in assessment.

One could argue that hazard assessment is the NUMBER ONE priority for preventing confined space entry fatalities.  A hazard that is not identified cannot be eliminated or controlled. 


NFPA is developing a best practices document for confined space entry.  Hazard assessment will be an important part of this document. How do you insure that all hazards are identified in your confined spaces?  Do you use a checklist/permit?   How competent is the person who is evaluating your confined spaces?   Do you include a list of hazards that will be brought into the space as a result of work being performed?What about adjacent spaces (see previous blog)?

If you have suggestions for what should be included in the hazard assessment or in the new document in general, please let us know!


The existing OSHA 1910.146 Permit Required Confined Space

Standard for general industry does not address hazards immediately outside and

adjacent to confined spaces.   Atmospheric

hazards adjacent to a confined space create both health and safety

hazards.   Fatalities have occurred when

workers were overcome by toxins present in the vicinity of the confined space. Flammable

atmospheres have been the source of numerous fatalities that have occurred when

a worker was performing hot work immediately outside a confined space.  Two employees at Valero Refinery died when

they were overcome by nitrogen as they performed maintenance work near a confined

space opening on the top of a reactor.  A worker at DuPont was killed when he was

welding immediately outside a tank containing flammable vapors.

These fatal accidents may have been prevented if the
atmosphere outside these two confined spaces had been tested.   How do we address those hazards that are not
necessarily inside the confined space but are very much associated with the
confined space hazard?  


In the marine industry, both the OSHA Shipyard standards

(1915.14) and NFPA 306 Standard for the Control of Gas Hazards on Vessels

recognize the hazards of adjacent spaces. 

 Both standards require that a Marine

Chemist evaluate not only the confined space but also the area adjacent to those spaces whenever hot

work such as welding will take place.  

NFPA is developing a best practices document for confined
space entry.  The new document is designed to address gaps in existing confined space standards and will
likely include the evaluation of hazards in the area adjacent to the confined

If you have suggestions for what should be included in this
soon to be developed new confined space best practices document we would love
to hear from you.    Should the document
address hazards immediately adjacent to confined spaces?  Is there a gap in the current OSHA general
industry standard that should address these hazards? We want to hear from you!

A video on the Valero incident

You have identified all your confined spaces at your workplace.  What is next?  You need to figure out when and why employees may need to enter those spaces.   The best possible scenario is that you make the determination that there is NO NEED for employees to enter this space or at least not to enter except in unusual circumstances.  In those cases you need to take steps to insure that these spaces are NOT entered.  Sometimes it takes a fresh look at some of your confined spaces to see if it necessary to go in to those spaces at all.  The safest option for entry is no entry at all.  

A few years ago I was working with a correctional facilities manager to develop a confined space entry program for the facility.   He brought me in to the laundry room and showed me a vertical pipe chase in the corner of the room leading several stories down to the basement.  The pipe chase had a grate covering over the opening.   The facilities manager indicated that occasionally someone would have to open the grate and descend to the basement to retrieve socks and other items that had fallen through the grate.   The logical question “Why put employees at risk entering a confined space to retrieve a sock?”  Certainly we all have mismatches to deal with!   In this case there was also a very logical solution.   Put a fine mesh screen over the hole below the grate so nothing falls in! Then lock the grate shut, post a confined space label and if there is a need to enter the space every 20 years to repair a leaking pipe, then review the hazards of the space and safe entry procedures prior to entry. 

Technology is available today that can minimize the need for confined space entry.  In the past, meter readers had to enter confined spaces such as vaults and manholes routinely to manually read water and electrical meters.  There are now remote reading sensors that can be installed so that these same meters can be read without entering the confined spaces.   Video cameras can be used to “monitor” spaces and electronic detectors can sense when a valve or gasket may be leaking.   A valve stem could be extended so that it can be manipulated from outside a confined space.  We need to start figuring out ways to NOT enter confined spaces! (More on prevention through design in a later blog!)   

 If you determine that there are confined spaces in your workplace that you do not want employees to enter, the OSHA 1910.146 (c)(3) of the  Permit Required Confined Space Standard 

 allows employers to post a sign warning of a confined space hazard, take effective means to prevent entry, and re-evaluate the space if an employee and contractor were to enter the space.  

Do you have any examples of confined spaces at your workplace that do not need to be entered?   I would love to hear about them and what you did to prevent entry!   Remember, the safest entry is NO entry!!

The first step in developing a confined space program is to identify these spaces in your workplace.   Many confined space fatalities have occurred because an employer failed to recognize the presence of a confined space.   While there are several different definitions of what constitutes a confined space, one characteristic is consistent and stands out above the rest-a confined space is NOT DESIGNED FOR HUMAN OCCUPANCY.  I once heard an instructor say that if you cannot or would not comfortably put your desk in a space and work there all day then your radar should go up and you should think “possible confined space”.  A confined does not necessarily have to be small and “confined” it simply has to be “not designed for continuous human occupancy”.   While spaces such as sewer manholes, vaults and tanks may be more readily identified as confined spaces, there are other spaces such as tunnels, vaults, crawl spaces, pipelines, boilers, water reservoirs, ship holds and elevator shafts that may not be as recognizable as confined spaces.  A tank that held petroleum may be clearly recognized as a confined space due to the chemical vapors. However a tank that has only held water may not be recognized as a confined space. Yet a rusted water tank could contain a low oxygen atmosphere.    

Another key characteristic of a confined space is that it has a limited or restricted means for entering and exiting the space.  What does this mean?  It means you cannot just walk directly into the space through a doorway or down a set of standard stairs to access the space.  Typically  access to confined spaces is via a ladder or perhaps a spiral staircase or through a hatch or small opening.  Sometimes you must contort your body or crawl to work in, get into or get out of the space.    One such example would be a shallow crawl spaces with lots of pipes obstructing access or egress. 

A full audit of your workplace should be done to determine if there are any confined spaces present. OSHA 1910.146 Permit-Required Confined Space Entry Standard requires employers to evaluate the workplace to determine if there are any confined spaces.  Once identified, these spaces must be labeled and employees informed of the presence of such spaces.   OSHA does identify the characteristics of a confined space but does not specify the competencies required of the individual who will evaluate the workplace to determine if confined spaces are present.  

NFPA 306, Control of Gas Hazards on Vessels, requires a marine chemist with specific qualifications for evaluating confined spaces on marine vessels.  There is no such requirement for other industries although the American Petroleum Institute does have a certification program that provides a body of knowledge for those who serve as API certified tank entry supervisors.

Do you have someone in your workplace qualified to identify the presence of a confined space?   Once identified, can theis individual identify the hazards in those confined spaces anddo they know how to eliminate or control those hazards?  

The NFPA technical committee on confined spaces will be developing a best practices guide for confined space entry. One possible topic we may include in this document is the training/competencies required for evaluating the presence and hazards of confined spaces.  What type of qualifications do you think someone should have to be able to identify confined spaces and their hazards? Do you feel that this evaluation needs to be done by a safety or health professional or simply by a knowledgeable individual who has been trained to recognize confined spaces?  Let us know what you think! 

 (Next blog topic-Identifying Hazards in Confined Spaces)

The OSHA Permit Required Confined Spaces standard, 29 CFR 1910.146, is perhaps the most widely known confined space standard. It provides practices and procedures to protect employees in general industry from the hazards in permit-required confined spaces. The 1910.146 standard does not apply to agriculture, construction or shipyard employment. OSHA’s 1910.272 standard provides basic guidance for entering confined spaces in grain handling facilities. 1915 Subpart B of OSHA provides requirements for entering confined and enclosed spaces in shipyard employment. To date OSHA does not have a confined space entry standard for the construction industry. A proposed rule was published in 2007 and it is on OSHA’s current regulatory agenda. Extensive information on confined space entry can be found on OSHA’s confined space topic page .

There are a number of organizations with consensus standards that relate to confined space entry. The National Fire Protection Association (NFPA) has several consensus standards. NFPA 306 ,Standard on the Control of Gas Hazards on Vessels, provides minimum requirements for entry into vessels that carry hazardous materials in shipyards or ship repair facilities. This standard requires the use of a marine chemist to issue a certificate describing conditions for entry and work in a confined space. NFPA 326, Standard for the Safeguarding of Tanks and Containers for Entry, Cleaning, or Repair, includes minimum procedures for removing hazards prior to entering a tank that may have contained hazardous materials prior to repair including hot work.  NFPA 1670 ,Standard on Operations and Training for Technical Search and Rescue Incidents, includes a chapter on confined space rescue. This chapter describes the requirements for organizations responsible for confined space rescue.

The American Society of Safety Engineers (ASSE) has developed a consensus standard ANSI/ASSE Z117.1, Safety Requirements for Confined Spaces. The original standard was published prior to the OSHA standard. It describes minimum safety requirements to be followed while entering, exiting and working in confined spaces. 

Industry specific consensus standards have been developed by the American Petroleum Institute (API). ANSI/API 2015, Requirements for Safe Entry and Cleaning of Petroleum Storage Tanks, provides requirements for entry and work being performed in stationary tanks used in all sectors of the petroleum and petrochemical industry. ANSI/API 2016 ,Guidelines and Procedures for Entering and Cleaning Petroleum Storage Tanks, provides additional guidance and supplements the requirements of specific aspects of tank cleaning given in the ANSI/API 2015 standard. 

Most of the standards currently in existence provide minimum requirements for entry. They are generally not prescriptive but are performance based leaving the employer or safety professional to decide how to best evaluate, enter, work in and exit the space. There are still approximately 100 employees a year killed in confined spaces. As safety and health professionals we need to do a better job preventing these fatalities.

The new document that will be developed by the NFPA technical committee is expected to go above and beyond the minimum requirements and will provide more detailed guidance on evaluating confined spaces and controlling hazards. It is expected that this document will extract some of the best practices from existing documents and will include additional recommendations for evaluating, entering, working and exiting confined spaces.

We are hoping this document becomes a “gold standard” for confined space entry. What would you like to see included in this type of document? Let us know!

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