Confined space rescues can be technically challenging due to the environment in which they occur. Confined spaces are often narrow and constricting preventing easy access by rescuers. They are usually either unlit or poorly lit so rescuers must provide their own light source. Finally, confined spaces often contain hazardous materials in liquid or gas form which can be harmful or fatal to humans.
These hazards can be fatal as they create a limited window in which to perform a rescue. The general rule is that after four minutes without oxygen, a person in a confined space will likely suffer asphyxia resulting in either brain damage or death. The urgent need to rescue someone from a confined space often leads to ill-prepared rescue attempts. Two-thirds of all of deaths occurring in confined spaces are attributed to persons attempting to rescue someone else.
In the event of an entry rescue, standby rescuers are recommended in the event that the initial entry rescuer(s) encounter trouble.
A wristlet is often the first item used to actually perform the rescue, as opposed to the ventilator which is used to prepare the environment for a rescue. A wristlet is a cloth strap that is used to cinch tightly around the wrist or ankle of an incapacitated person. Once the strap is looped around a hand or foot, its attached rope is pulled by rescuers, tightening around the arm or leg and pulling the victim out of the confined space.
In the event that an entry rescue must be performed, rescue personnel will wear protective clothing appropriate for the situation. This may include a self contained breathing apparatus (SCBA), protective headgear and the use of explosion proof lighting (to preventigniting any gases). The rescuer may also wear a full body harness with an attached safety line, especially if a vertical descent is required. To assist in vertical descents, a mechanical winch and tripod may be set up over the access point, if the bottom of the confined space is more than five feet from the entrance.
The rescuers may also carry monitoring equipment by which they can ascertain the quality of the air in the environment. Even if the air quality reading does not indicate any hazardous conditions, it is still recommended that rescuers wear SCBA.
Numerous agencies in the United States have facilities for technical rescue training and often have a confined space training area.
In the USA, confined space rescue is covered under the National Fire Protection Association (NFPA) 1670, and under 29 CFR 1910.146 and 29 CFR 1910.147, and often is managed according to the Incident Command System.