I've been coming to this site for awhile now and have got some good information here. That is why I come to you all with this question. I work in a factory which getting ready to partake in the OSHAS 18001 safety program. I don't know if anyone is familiar with this or not, but as the electrician and maintenance guy on sight I was asked to check the grounding system of the building. I'm not really sure what kind of checking they want me to do, but I thought maybe someone here has done this sort of thing before and could give me a heads up on maybe what they want and how to do this. I called the AHJ for this area and he didn't really know of anything to tell me. Thanks for your help.

Rent a Biddle Ground Tester from a rental place that has such equipment. Read the instructions and do as they recommend. Have a set of your building drawings available so you will know where the ground test wells are located.
Good luck.

Start by finding out what OSHA 18001 standards call for. If grounding is your only concern, I would find a book that will guide you through the NEC, and give you a better understanding of system grounding, circuit grounding, equipment grounding, performance of fault current path, etc., etc., etc.
Whatever 18001 calls for, find as much information about those subjects, and break your facility down into systems, or sections, and systematically work them all until you meet 18001 requirements.
Also, take 2 asprins, and call me in the morning.
Regards,
Doc