According to OSHA, there are three characteristics of confined spaces:

• It is big enough for a person to fit his or her entire body.
• It is restrictive for the person when he or she is entering and exiting.
• The space is not meant for someone to stay in for a long period of time.

There are many rules associated with entering a confined space but perhaps the Golden Rule of them all is Check and Monitor the atmosphere before entering. In the following article a failure to do such became deadly:

One by one, 3 utility workers descended into a manhole. One by one, they died.
The Washington Post January 18, 2017
By Samantha Schmidt

When a utility worker in Key Largo, Fla., noticed that a section of a paved street was not settling properly, he decided to remove a manhole cover and descend into the earth.

Moments later on Monday morning, the 15-foot-deep hole went silent. Sensing the man was trapped, a fellow utility worker climbed into the drainage hole to rescue him. When he, too, stopped responding, a third worker entered the same hole.

All three men died, overcome by poisonous fumes underground, the Monroe County Sheriff’s Office said in a statement. A Key Largo firefighter who made a desperate attempt to save the men also became unconscious within seconds. The firefighter, Leonardo Moreno, an eight-year veteran of the department, was flown to a hospital and was in critical condition Tuesday.

The hole, just wide enough to fit a body, was filled with hydrogen sulfide and methane gas created from years of rotted vegetation, the Miami Herald reported. None of the four men wore masks or carried the air packs that could have likely saved their lives. Moreno descended into the hole without his air tank because he could not fit through the hole with it, according to Monroe County Sheriff Rick Ramsay.

OSHA has very specific rules for confined space entry and work. In general they can be outlined as the following:

• Monitor the atmosphere
• Eliminate or control hazards
• Ventilate the space
• Use proper personal protective equipment
• Isolate the space
• Have a trained attendant
• Be prepared for rescues
• Plan for emergencies
• Emphasize constant communication

It's critical that we each follow all the procedures put in place to ensure each of us goes home after the work is done. It's so easy to get caught up in the moment and try to help out and yet become a victim ourselves.