just go to osha .gov and look up powder actuated tool.
heres a snip:
Powder-Actuated Tools
Powder-actuated tools operate like a loaded gun and should be treated with the same respect and precautions. In fact, they are so dangerous that they must be operated only by specially trained employees.
Safety precautions to remember include the following:
These tools should not be used in an explosive or flammable atmosphere.
Before using the tool, the worker should inspect it to determine that it is clean, that all moving parts operate freely, and that the barrel is free from obstructions.
The tool should never be pointed at anybody.
The tool should not be loaded unless it is to be used immediately. A loaded tool should not be left unattended, especially where it would be available to unauthorized persons.
Hands should be kept clear of the barrel end. To prevent the tool from firing accidentally, two separate motions are required for firing: one to bring the tool into position, and another to pull the trigger. The tools must not be able to operate until they are pressed against the work surface with a force of at least 5 pounds greater than the total weight of the tool.
If a powder-actuated tool misfires, the employee should wait at least 30 seconds, then try firing it again. If it still will not fire, the user should wait another 30 seconds so that the faulty cartridge is less likely to explode, than carefully remove the load. The bad cartridge should be put in water.
Suitable eye and face protection are essential when using a powder-actuated tool.
The muzzle end of the tool must have a protective shield or guard centered perpendicularly on the barrel to confine any flying fragments or particles that might otherwise create a hazard when the tool is fired. The tool must be designed so that it will not fire unless it has this kind of safety device.
All powder-actuated tools must be designed for varying powder charges so that the user can select a powder level necessary to do the work without excessive force.
If the tool develops a defect during use it should be tagged and taken out of service immediately until it is properly repaired.