Tony,

For maybe for the first time in the few years I have followed this
list a topic has appeared that I am actually quite knowledgeable
about and that is health and safety. "Lead vapor", fumes, or dusts
are actually the most dangerous route of entry (inhalation) for
lead. It gets into the blood stream quite quickly and completely
through the lungs. Ingestion (eating or through the mouth) is
usually a secondary route of exposure for adults and less of the
product is absorbed into the blood stream. Ingestion is the primary
route of exposure for children whose "safe" exposure levels are about
1/5 that of an adult when using blood lead levels to measure
exposure. Children are much more susceptible to lead exposure as it
can effect brain development (it doesn't take much). Adult's brains
are pretty much developed so on average they can tolerate higher
levels of exposure without negative affect to the brain, but then the
issue becomes other organs. Target organs in adults include: Eyes,
gastrointestinal tract, central nervous system, kidneys, blood, and
gingival tissue.

http://www.cdc.gov/niosh/npg/npgd0368.html is the pocket guide page
from NIOSH and gives general information about exposure levels for
adults. Translating the numbers, I personally might melt lead
outside, keeping my face away from the "pot" most of the time and
staying up wind. And I would only do it on very limited occasions as
over time blood lead levels can reduce without repeated exposures.
When handling lead sheets as I do at the modeling work bench, I make
it a habit to wash my hands just after handling leada to reduce the
chance of ingestion. I agree a certain amount of "care is needed" but
that includes vapors and dusts.

Regards,
Bruce D. Griffin, MSOS, CSP

--- In STMFC@yahoogroups.com, Anthony Thompson <thompson@...> wrote:

Garth G. Groff wrote:

I know we've disagreed about this before, and I certainly respect

your

scientific knowledge. However, my father used to melt lead tire
weights just as described. He was later diagnosed with lead

poisoning.

Handling lead with bare hands gets the oxide onto your skin,

and

may get it into your mouth or nose. I'd worry about that part, not
about the lead vapor.
Please do not think I was saying lead is harmless or that you

can

treat it cavalierly. Care is needed.
And by the way, Garth, if your father is 91 the lead must

not

have been TOO bad for him <meant in jest, of course>.

Tony Thompson Editor, Signature Press, Berkeley, CA
2906 Forest Ave., Berkeley, CA 94705 www.signaturepress.com
(510) 540-6538; fax, (510) 540-1937; e-mail, thompson@...
Publishers of books on railroad history