1.       They do not recognize a confined space.

A confined space has few ways in or out and it may be difficult to get into or out of. It is not intended to be occupied by human beings on a regular basis and it may contain a hazardous atmosphere or other recognized safety and health hazards.

2.       They trust their senses.

We think that if a space looks safe, it is safe. But most hazardous atmospheres are invisible. You cannot see, taste or smell most toxic and deadly atmospheres.

3.       They under estimate the danger.

Before you finish reading a simple eighteen words sentence like this one, methane gas can knock you out. Exposure to some organic vapors may not kill you until the next day. Before entering a confined space, the person supervising the crew going in should make sure of the following:

• the personnel entering the space is knowledgeable of the hazards and has proper safety equipment;
• the volume is isolated, at atmospheric pressure and tagged;
• the monitoring requirements have been established and the area is properly posted.

4.       They do not stay on guard.

Often, a person will forget that a hazard may develop after he has entered a space. Sometimes, the work you are doing inside the confined space causes the atmosphere to become deadly. If this is a possibility, testing for the space must be an ongoing process, not just something you do before someone enters.

5.       They try to rescue other people.

It is human nature to help a person in trouble. But the sad fact is that untrained rescuers usually die along with the victim they are trying to save. Holding your breath is not enough protection in a confined space that is filled with a hazardous vapor, is oxygen deficient, or is blanketed with smoke. Calling for help is the most important thing you can do to save the life of a person who is unconscious in a confined space. Only if you have appropriate rescue equipment and personnel available should a rescue attempt be made.