Sunday, April 20, 2014

Risk Assessment in a Small Autobody Shop

This week’s blog does not get into the technical aspects of modeling but more into a lesson in the human aspects of worker exposure/risk assessment that I received as a young man.

When I was a graduate student, many years ago, I attended a neighborhood New Year’s Eve Party.   While doing some social drinking and hanging out with my neighbors, I mentioned that I needed to find a real world project to complete my Master’s Degree program at Drexel University.   They all knew that I was in the field of Industrial Hygiene.   One of the folks at the party said: “ You should  come over to our autobody shop.  We get high a few times a week on the paint fumes. “   He did not have to suggest it twice!    I spent time in that shop every day I could for the next year, including most of my vacation days, measuring airborne vapors, particulate and metals along with noise.  

It was a two-man, jointly owned and operated “bump and paint” shop.  It was extremely difficult work, almost all of it was stoop label, spent bent-over the surface of an automobile cutting, hammering, applying resin or sanding.   Relatively little time was spent doing actual painting.  It was all “piece work” – that is, they were paid by how much work they got done.   As such, they worked hard with few breaks for 10-12 hour days during the week and half a day on Saturday.

The never saw anyone from OSHA but they did have to have insurance and for that they had to have a good hood for painting whole cars.   The hood was large enough to hold a car with enough room for a painter to spray paint it.  It had a band of filters and a large fan that provided 100-150 linear feet per minute flow over the filters comprising the entire wall at its far end.   Spraying an entire car took less than an hour and when the hood was running the breathing zone concentrations of paint vapor or particulate were well below any of the then current OELs; however, they could not always run the hood.

All of the air going through those filters was exhausted outside.   When the outdoor temperatures got below 50F, the heating system in the garage (100,000 BTU/hr from the main heater + 50,000 BTU/hr  from two kerosene space heaters) could not keep up with the loss of warm air and the owners would run the hood either intermittently or turn it off completely.   Suffice it to say that the airborne and breathing zone concentrations went up dramatically.  Indeed, it was not unusual to see the painter emerge from the booth visibly intoxicated.   What was particularly noteworthy to this young investigator was to see him prolong the experience by then drinking a beer!

One day, before I went to my work, I hung an integrating sound monitor on one of the workers who advised he was going to do a “chop job” that day.    This apparently involves cutting two wrecked cars in half and joining the good halves of each to make one good car which I assume wound up on a used car lot somewhere. (Buyer beware!).  This is done with a pneumatic device called a “chipper”.   When I evaluated the dosimeter that evening he had received 160% of an allowable daily noise dose (8 hr/90dbA Standard – 5 dB doubling rate).

The bottom line for these workers and their risk was that they were subjected to intense levels of potential overexposure but of limited duration.    The use of a reasonably well fit half-faced mask with the appropriate canisters and filters for a few hours a week would have protected them from overexposure to vapors or particulates. Similarly, the use of hearing protection during the limited times where noise levels were high would have also protected their hearing.

I was eventually, able to get this work published but my first experience with the American Industrial Hygiene Journal peer reviewers was personally crushing.   They were so critical and dismissive of the work that if I believed their comments I would have left the field of Industrial Hygiene.    I submitted the work to the journal of the British Occupational Hygiene Society and their reviewers were much kinder to a young author.

If you are interested in a copy of this paper, please send me a request at

Toward the end of the study, my wife and I invited both of my neighbors and their wifes over for a roast-beef dinner.  After dinner I presented them with a draft copy of the report and told them what they could do to protect their health from these potential overexposures.   I would love to report that they took all the advice but I think you know that is not a realistic expectation.  



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