The following is the abstract from a study done by the following doctors: O. H. ROBERTSON, CLAYTON G. LOOSLI, THEODORE T. PUCK, HENRY WISE, HENRY M. LEMON and WILLIAM LESTER, JR. It is entitled: TESTS FOR THE CHRONIC TOXICITY OF PROPYLEXE GLYCOL AND TRIETHYLENE GLYCOL ON MONKEYS AND RATS BY VAPOR INHALATION AND ORAL ADMINISTRATION "With a view to determining the safety of employing the vapors of propylene glycol and triethylene glycol in atmospheres inhabited by human beings, monkeys and rats were exposed continuously to high concentrations of these vapors for periods of 12 to 18 months. Equal numbers of control animals were maintained under physically similar conditions. Long term tests of the effects on ingesting triethylene glycol were also carried out. The doses administered represented 50 to 700 times the amount of glycol the animal could absorb by breathing air saturated with the glycol. Comparative observations on the growth rates, blood counts, urine examinations, kidney function tests, fertility and general condition of the test and control groups, exhibited no essential differences between them with the exception that the rats in the glycol atmospheres exhibited consistently higher weight gains. Some drying of the skin of the monkeys' faces occurred after several months continuous exposure to a heavy fog of triethylene glycol. However, when the vapor concentration was maintained just below saturation by means of the glycostat this effect did not occur. Examination at autopsy likewise failed to reveal any differences between the animals kept in glycolized air and those living in the ordinary room atmosphere. Extensive histological study of the lungs was made to ascertain whether the glycol had produced any generalized or local irritation. None was found. The kidneys, liver, spleen and bone marrow also were normal. The results of these experiments in conjunction with the absence of any observed ill effects in patients exposed to both triethylene glycol and propylene glycol vapors for months at a time, provide assurance that air containing these vapors in amounts up to the saturation point is COMPLETELY HARMLESS.

and yeah I'm sure OSHA is completely up to date with info... "during the 1970s the agency had one inspector per 30,000 workers; now it's one per 60,000. The fact is that the agency essentially has no enforcement authority. Moreover, over the past decade, OSHA has issued only one new health standard to clarify the maximum safe exposure level for a chemical--and this was done under a court order."