Industrial Supply Blog

Confined Space Entry for Oil and Gas Workers

Oct 24, 2017 6:09:04 AM

Confined space entrance

Confined space entry is not uncommon in the oil and gas industry. Workers are often required to enter spaces for inspection and maintenance. The workers who enter these spaces expose themselves to very serious hazards.

It’s important for you to have a confined space entry program at your facility.. This program should include training, equipment, and policies/procedures. With a program in place, you reduce the risk of injuries associated with confined space entry.

What is a confined space?

OSHA has set forth some very clear definitions of what a confined space is. First, it’s important for you to understand that there are two different kinds of confined spaces.

Non-Permitted Space

This type of confined space is a very basic, low-hazard area.

OSHA defines a non-permitted confined space as a “space that does not contain or, with respect to atmospheric hazards, have the potential to contain any hazard capable of causing death or serious physical harm.”

Non-permitted spaces do not require any specific safety precautions. Yet, employees should always let someone know that they are entering a space.

A non-permitted space has the following characteristics:

  • The space is large enough for an employee to enter and perform assigned work
  • The space has limited or restricted means for entry or exit
  • The space was not designed for continuous employee occupancy

Some example of non-permitted spaces in the oil and gas industry include:

  • Tanks
  • Bins
  • Mud pits
  • Reserve pits and other excavated areas
  • Sand storage containers
  • Other spaces around a wellhead

Permit-Required Space

A permit-required space includes all the characteristics mentioned above. But it also contains additional hazards.

To classify a space as “permit-required,” it must also contain at least one of the following:

  • Contains or has the potential to contain a hazardous atmosphere
  • Material that has the potential for engulfing an entrant
  • Internal configuration such that an entrant could be trapped or asphyxiated by inwardly converging walls, or by a floor which slopes downward and tapers to a smaller cross-section
  • Any other recognized serious safety or health hazard

Those who work in the oil and gas industry know that any of the above hazards are possible. Work inside confined spaces often involves welding or the use of chemicals. Materials in pits and excavated areas could engulf entrants. And many bins and spaces are oddly-shaped, and often taper downward.

Permit-required spaces have extra safety precautions that employees must follow before entering. Both the employer and the employee have responsibilities to fulfill.

Employer must:

  1. Implement measures necessary to prevent unauthorized entry
  2. Provide training to all involved and affected employees
  3. Identify and evaluate hazards of spaces specific to their facility
  4. Develop and maintain procedures for safe entry
  5. Provide and maintain confined space entry equipment
  6. Name an attendant to stand watch outside of the space before, during, and after entry
  7. Develop and implement rescue plans and procedures
  8. Maintain records of confined space entries

Employee must:

  1. Never enter a space without training
  2. Never enter a space without a permit to do so
  3. Review, understand and follow employer's procedures before entering; know how to exit
  4. Before entry, identify any physical hazards
  5. Test and monitor oxygen content, flammability, toxicity or explosive hazards as necessary
  6. Use employer's confined space equipment according to entry procedures
  7. Maintain contact at all times with a trained attendant. Either visually, via phone, or by two-way radio


workers welding in a confined space

What are the hazards of confined space entry for oil and gas workers?

Many hazards can be present in confined spaces. The hazards will depend on the size and configuration of the space. It'll also depend on the work performed inside the space. Here are some examples of common confined space hazards:

Atmospheric Hazards

Most deaths associated with confined space entry are due to atmospheric hazards. Because the spaces are so small, these atmospheres can quickly overcome an employee. These sudden and unexpected hazards can interfere with evacuation. The main atmospheric hazards are:

  • Toxic gases and vapors
  • Flammable gases and vapors
  • Oxygen rich or oxygen deficient atmospheres

The four main gases in confined spaces are oxygen, carbon monoxide, hydrogen sulfide, and explosive materials. Below is a brief description of the various hazards for each of these gases. Want more info on deadly gases in the oil and gads industry? Check out our informative blog, "The Top 5 Deadly Gases in the Oil and gas Industry".



Oxygen can be hazardous both when there is too much and when there is too little. When there is too little oxygen (below 19.5%), workers can start to feel dizzy and lose consciousness. Too much oxygen will produce a hotter and faster burning fire if something were to ignite. 

Carbon Monoxide

Carbon monoxide, or CO,  is a colorless, odorless gas. It is poisonous when excess levels are inhaled. CO results when carbon-based materials are insufficiently burned. CO is often generated from hot work activity and mobile equipment exhaust. It's also present in oil and natural gas. Read OSHA’s Fact Sheet to Learn More

Hydrogen Sulfide

Also known as H2S, hydrogen sulfide is a colorless, flammable gas that has a distinct “rotten egg” odor. It occurs naturally in some environments. But the decomposition of organic material can also generate H2S. Exposure to H2S can result in irritation to the eyes and lungs, nausea, and headaches. High levels can result in shock, convulsions, unconsciousness, and death. Read OSHA’s Fact Sheet to Learn More

Explosives -- LEL’s

We measure flammable gases as LEL’s, or lower explosive limits. LEL’s represent the lowest concentration of gases or vapors that are capable of producing a flash fire. Welders, pipefitters, and other maintenance workers should use extra caution. 


Confined spaces can present hazards of excessive noise. Consider using hearing protection for all confined spaces. Particularly if the work involves hammering, pounding, or the use of powered equipment.


Most confined spaces will be dark upon entry. Consider using headlamps, flashlights, or other means of providing extra light. A well-lit work space reduces the risk of worker injury. Remember to use intrinsically-safe lighting in a confined space. Combustible gases could cause an explosion or flash fire if ignited. For more info on ignitiion sources in oil and gas read our blog, "Fire Prevention for the Oil and Gas Industry".

Equipment Mechanisms

Your company should already have a lockout tagout program in place. Follow applicable lockout procedures before entering confined spaces. That might include the space itself and/or equipment inside the space.

Worker entering a confined space

What equipment do I need to enter a confined space?

OSHA standard 1910.146(d)(4) states that the employer must “Provide the following equipment at no cost to employees, maintain that equipment properly, and ensure that employees use that equipment properly.”

Testing and monitoring equipment

4-Gas monitors are the main testing equipment you’ll need to provide. A standard monitor will measure the four gases discussed earlier.

Ventilating equipment

Ventilation equipment is necessary for spaces that do not have adequate air supply. You can pump air into the space with the right kind of equipment.

Communications equipment

It’s important for the entrant to maintain communication with the attendant. Phones or 2-way radio systems work well for this.

Personal protective equipment

It’s up to the employer to provide the necessary personal protective equipment (PPE). Basic PPE for confined space entry includes:

  • The employee's normal workwear
  • A harness for emergency retrieval
  • Respirator (depending on the work and atmospheres)

Emergency rescue equipment

Rescue equipment includes a harness and extraction device. Employees should use emergency retrieval mechanisms whenever possible. OSHA does not require a harness in all confined space entries. But some sort of rescue plan must be in place.

Lighting equipment

Employees should use intrinsically-safe lighting equipment. Headlamps and portable lighting units are popular options for working in confined spaces.

Barriers and shields to use around the space

Barricade equipment will block off access to a confined space. The attendant should be managing the entrance of a space while a person is already inside. But when a space is evacuated or left uncontrolled, barriers may be necessary.

Access equipment, such as ladders

Depending on the the space, special access equipment may be necessary. But most spaces can be accessed using basic equipment that you already have on hand.

Not all this equipment is necessary for every confined space entry. It will depend on the specific space and the nature of the work in that space. In general, the employer should always keep this equipment accessible.

What else to consider for confined space entry

The greatest danger in confined space entry is when workers underestimate the hazards that might be present. You never know what kinds of hazards you will encounter when working in a confined space.

That’s why it’s important to train employees on the risks of confined space entry. Provide them with the equipment and information that could save their lives.

Topics: Confined Space, Oil and gas

Subscribe to Email Updates

2019 State of Oil & Gas