Cal/OSHA PEL: HCl and HF Perspectives
We live in a society where numbers rule. Numbers rule in the way agencies do risk assessments. Numbers rule in the way chemicals are controlled in the workplace. It is therefore essential that worker exposure numbers properly convey hazards and in an absolute manner and in perspective to other potential hazards.
We respectfully suggest that as concerned individuals you provide constructive input to the Cal/OSHA PEL process. Cal/OSHA, a State agency that sets legally-enforceable worker exposure limits, is developing recommendations for several chemicals of interest to industry. Worker inhalation levels are under consideration for hydrogen chloride (HCl) and for hydrogen fluoride (HF).
HF is hydrogen fluoride in the gas phase or hydrofluoric acid in the liquid phase. HF is extremely toxic; exposure to HF can be lethal. HCl is hydrogen chloride (gas) or hydrochloric acid (liquid). HCl has been in common usage for centuries. While all chemicals must be managed with appropriate respect, HCl does not have anywhere near the observed problems seen with HF. Here are the levels for the two compounds. The level for HF has been proposed by HEAC; the level for HCl is under discussion by the HEAC.
|HF (a)||1 ppm||0.4 ppm|
|HCl (b)||2 ppm||0.3 ppm|
a. PEL project substance list as of 6/09; http://www.dir.ca.gov/dosh/DoshReg/5155Meetings_2009.htm
b. J. Unmack, Memo to HEAC, Question of TWA for HCl, June 22, 2009
STEL is the short term exposure limit, usually 15 minutes. TWA is the Time Weighted Average, Permissible Exposure Limit (PEL). HEAC is the Health Expert Advisory Committee, a volunteer group that recommends worker exposure limits to Cal/OSHA based on risk assessment.
Please notice that the numbers for the two compounds are essentially the same, yet hazards to workers are markedly different. We are concerned that the levels under discussion, if adopted, would not reflect potential hazards in a realistic manner. Certainly, worker exposure numbers for two different compounds do not always “match up,” particularly if evaluations are performed by geographically and culturally different agencies or if one inhalation level was set in, say, 2008 and another was set decades earlier. However, it would seem reasonable for there to be internal consistency within one group or agency at a given point in time.
James Unmack, of Unmack Everett Environmental, Inc. in Torrance, CA is an Industrial Hygienist with decades of experience in worker protection. Jim has been a member of the (HEAC); for essentially two years; and in that capacity, he has been providing his expert assessment and evaluation regarding appropriate worker exposure to HCl. Jim forwarded a document expressing his concern (“Hyperplasia Not an Issue with Hydrogen Chloride”). We are pleased that Jim is also a member of the Technical Advisory Panel of SQRC and appreciate his contribution to this article.
Willits Still Needs a Medical Monitoring Clinic
It’s déjà vu all over again; but the bottom line is, there is still no medical monitoring clinic for Willits. We support a medical monitoring clinic. Such a clinic would help the people in Willits. Understanding more about the impact of industrial chemicals would also be expected to help regulatory agencies like Cal/OSHA to develop approaches to protecting workers. It would help workers, manufacturers, and communities to avoid problems in the future. We have discussed the Abex/Remco facility and concerns over possible impact on workers and on people who were near the plant. Please see Green Source archives.