Paper coated with red lead

Peng-Peng Wang <ppwang [at] ix__netcom__com> writes

>People questioned the safety of handling this red lead treated
>paper. I looked at all the publications at hand and found nothing
>mentioned about the toxicity of red lead.

According to an article  on "The Preservation of Paper: Traditional
Chinese Methods"  by Chen Renyi published in the newsletter of the
Sun Ho Memorial Paper Museum in Taipei, Taiwan (Spring Issue,
31.05.96), paper treated with red lead was often known as
"10,000-year red (wannian hong, in Mandarin) or "pest-repellent
paper" (fangdu zhi).  The red lead is lead textroxide (Pb3O4), which
is highly toxic and its ingestion can be fatal in small amounts. The
article says that it is highly stable and will not decay easily,
hence the "10,000-year red". It also says that according to
experiments carried out (details are not specified), there is no
evidence to suggest that it actually works as a pest repellent.

Another technique was to use so-called "yellow paper" (huang zhi)
produced by soaking the paper with a dye produced from the yellow
oak tree.  The alkalis contained in the dye were supposed to act as
a pest repellent. This dye has been found in papers from Buddhist
sutras stored at Dunhuang. Wild pepper was also used.

Here is the health information for lead textroxide according to the
most recent MSDS (Material Safety Data Sheet) available on the WWW
from the Physical & Theoretical Chemistry Laboratory at Oxford
University which describes it as a Severe Health Hazard (Life) and
rates a 3 (out of 4):

    Threshold limit value (TLV/TWA): 0.15 mg/m3 (ppm)

    Toxicity:   ld50 (ipr-rat)(mg/kg) -  630

    Carcinogenicity:
        ntp: no  iarc: no  z list: no  osha reg: no

    Effects of overexposure
        chronic effects resulting from low level exposure to lead
        compounds may include anemia, kidney damage, impaired
        eyesight, and lead build-up in the central nervous system
        (particularly the brain). Dust may irritate skin.

    Target organs
        none identified

    Medical conditions generally aggravated by exposure
        none identified

    Routes of entry
        none indicated

    Emergency and first aid procedures
         call a physician.

The MSDS also warns to avoid contact with skin, eyes or clothing.
It also states that  general or local exhaust ventilation should be
used to meet TLV requirements.  If there is adequate ventilation,
then no respiratory protection is required.  However, if there are
airborne concentrations which exceed the TLV, a high efficiency
particulate (HEPA) respirator is recommended; if the concentration
exceeds the capacity of the respirator, a self-contained breathing
apparatus should be worn.  For eye and skin protection, wear safety
goggles, uniform, apron, and neoprene gloves.

For more information consult the appropriate MSDS, as well as
NIOSH/OSHA manuals before considering any treatment.  See also:
<URL:http://physchem.ox.ac.uk/MSDS/L/lead_oxide,_red>

Hope this helps,

David Tremain
CCI Preventive Conservation Services
david_tremain [at] pch__gc__ca
613-998-3721
Fax: 613-998-4721

                                  ***
                  Conservation DistList Instance 11:92
                  Distributed: Thursday, May 14, 1998
                       Message Id: cdl-11-92-006
                                  ***