In regard to the discussions on lead tubing, I would suggest that
interested MMDers take a look at the following link:

    http://www.access.gpo.gov/nara/cfr/waisidx_99/29cfr1910a_99.html

This link will display a series of Occupational Safety and Health
Administration (OSHA)  Standards.  Select the file for 29 CFR 1910.1025,
Lead.  This standard is directed to places of employment where lead
exposure may be present.  (OSHA standards generally apply to businesses
with 10 or more employees).  The standard describes acceptable levels
of lead in the workplace, but more importantly for the rebuilder,
describes in Appendix A and Appendix B the safety precautions that
should be taken to minimize lead exposure...

According to OSHA, the permissible exposure limit is 50 micrograms per
cubic meter of air averaged over an 8 hour period.

Lead is a toxic substance according to the EPA, and it does appear on
the Superfund Amendment list of substances as a part of the Emergency
Planning and Community Right-to-Know Act (EPCRA) program.  Lead has an
EPA reportable quantity of 10 pounds (release of lead to the
environment) -- and states may have different rules regarding
notification and disposal.  Some particularly toxic lead compounds have
a 1 pound reportable quantity.  For the hobbiest though, most urban
areas have designed "hazardous waste" days (with specific disposal
locations) where households may discard solvents, used oil, paint, old
batteries, or crumpled tracker bar tubing.

Karl Van Scyoc
Houston Texas