In spite of although no reliable data in Brazil, it is known the expressive number of accidents at confined spaces work, that occur by the lack of knowledge of the risks and safety barriers necessaries. It is estimated that 90% of accidents in confined spaces are severe, usually more than one worker. In the past miners used to take birds to work, it was a fundamental precaution to realize the oxygen deficiency and toxic gases in the environments. If the bird produces any symptom or died, was a sign that something was wrong and everybody should leave the workplace immediately. Workers continue to enter in confined environments (tanks, ducts silos, vessels, galleries, boilers, etc), often without basic precautions and they are dying and suffering severe lesions not only by lack of oxygen, toxic products inhalation, falls or explosions, but primarily by lack of information. In general, only big companies have access to knowledge because they have a staff. The medium and small companies do not know the minimal necessary, only when occurs a fatality, they are aware of problem through newspaper, magazines or news.