I definitely want to advocate the use of masks when working under
buildings, especially those with poor to no ventilation.  I presently work
for the NPS at the NHL Kennecott Mill Town.  Recently we have done quite a
bit of work in building crawl spaces, including small scale excavation.
Our major danger is that all the buildings were painted with lead based
paints, even some of the floors were painted with lead paint.  Lead dust
has filtered into the crawl spaces of some of the buildings.  We wear
cartridge style face masks and tyvek suits.  Lead is very debilitating.  Of
course I forgot to mention the asbestos wrapped pipes which are also under
the foundations.


Tim Marshall
Archaeologist
NPS- Kennecott NHL