benzene, 1 1 1-Trichloroethane, M.T.B.E, chlorine, etc.) and metals
(lead, arsenic, mercury, cadnium, etc.) other toxic compounds include, Nitrous oxide, glue, ammonia, etc..)
4) Inflammation in the lower back which reduces blood flow to the nerves in the spinal column.
5) Sciatic nerve entrapment (piriformis entrapment) caused from standing on concrete too much, sitting too long in one position putting pressure on the sciatic nerve or its blood supply, and aging, where muscles lose tone.