Hi Brian,

I ran into the same problem on a manual conformal coating line.  Several
operators complained about headaches from a poorly designed (in-house)
ventilation system.  Most were willing to accept the headaches as part of
the job.  We had the Biological/Environmental office come down to do a site
survey.  First, we found three different places to measure airflow - at the
vent, at the work surface and at the operator's head (typical).  Everyone
got hooked up with sniffers and found that the exposure was well below the
MSDS levels.  The Bio/Enviro folks didn't even blink - wrote up the report
and ignored worker's reported symptoms.  I did notice the workers taking
extra precaution to limit their exposure by actually putting caps back on
bottles of thinner and taking more breaks for fresh air.  I left before
finding a cheap enough glove box to eliminate the exposure all together.

Hans  



-----Original Message-----
From: Brian Ellis [mailto:[log in to unmask]]
Sent: Wednesday, February 06, 2002 11:55 AM
To: [log in to unmask]
Subject: [EN] Operator Exposure Limits


Hi!

The environment of the worker is probably more important than THE
environment, in a way. I recently went into a factory that literally
stank of solvents from a coating (not electrical) drying process. My
nasal chromatograph analysed the stuff as mainly aliphatic paraffins,
with a soupçon of simple esters, neither of which are horrendously toxic
and my nasal detection tube said that the ppm of both substance types in
the actual workshop was way above the limit in the country concerned. As
this was not of direct concern to the purpose of my visit, I could not
take any action other than to make a simple remark, en passant, to my
interlocutor and to also query the fire hazard.

This has led me to wonder whether we, in industry, systematically
measure the exposure levels that operators are exposed to to check
whether they are within the limits. If so, are spot checks made
(detection tubes), passive carbon buttons or tubes worn or active tubes
worn. If so at what frequency and for what chemicals? What chemicals do
we use where no measurement is made (other than dihydrogen oxide).

Simply curious!

Best regards,

Brian