9 Lead Compounds 163Substances Data Bank provided by the National Library of Medicine. The US
Environmental Protection Agency has classified lead as a Group B2 (probable) car-
cinogen and as a Category I contaminant (which results in the Maximum Contaminant
Level Goal (MCLG) for drinking water being set at a value of zero) [40]. In response
to EPA’s classification, the State of California now regulates lead and lead compounds
through Proposition 65, which requires labeling of all products that contain cancer-
causing agents. The US Federal Drug Administration (FDA) also monitors lead expo-
sure, because fine dust can settle on food or lead can leach from lead-containing food
containers. Lead and lead compounds are regulated with respect to air quality stand-
ards, drinking water standards, and blood levels. Examples of some of these standards
are presented in Table 10.
From the environmental loading perspective, lead and lead compounds are regulated
by EPCRA (the Emergency Planning and Community Right To Know Act, 1986) as
a persistent, bioaccumulative, and toxic (PBT) chemical. As such the disposal and
release of these substances are subject to Toxic Release Inventory (TRI) reporting. In
2001, the threshold reporting level for lead and lead compounds was lowered from
5,000 to 220 kg per year. Results from the 2002 TRI Report [42] indicate that in the
United States over 440,000 tons of lead and lead compounds were disposed of or
released into the environment. This represents more than 97% of all PBT chemical
releases in that year. Lead and lead compounds are also regulated by RCRA (Resource
Conservation and Recovery Act, 1976). Thus, products that contain lead or lead com-
pounds must be treated as hazardous waste. Discards of lead from glass and ceramic
products into the municipal solid waste stream have been increasing, primarily as the
result of CRT disposal. The US EPA estimated that lead discards from TV glass
increased from 10,000 tons in 1970 to over 52,000 tons in 1986; lead discards from
light bulb glass increased from ~500 tons to almost 700 tons in the same period; and
for other glass and ceramic applications combined, the increase was from 3,300 tons to
almost 7,800 tons [43].
In the 1970s, a major concern was the documented evidence that the lead in lead-
containing glazes used on whitewares used as food containers and for cooking could
leach lead into food. The glass industry was responsive to these and related occupational
concerns, established appropriate operating procedures and monitoring systems, as
well as reduced the use of raw materials that were more soluble, such as lead carbon-
ates [14,15,31,44]. Later, leaching of lead from leaded crystal, especially that used for
wine decanters, became a concern [45]. This concern still exists, but is mitigated
Table 9Carcinogen levels and occupational exposure warnings for lead and various lead compounds [39]
Substance CAS No.a Carcinogen levelb Warningsc Reference
Lead 7439-92-1 A3 Dust, women ICSC 0052
PbO 1317-36-8 A3 Dust, women ICSC 0288
PbO 2 1309-60-0 A3 Women ICSC 1001
Pb 3 O 4 1314-41-6 A3 Women ICSC 1002
PbCO 3 598-63-0 A3 All contact ICSC 0999
PbCrO 4 7758-97-6 A2 All contact, dust, ICSC 0003
women, children
aCAS: Chemical Abstracts Services
bA3: Animal carcinogen; A2: Suspected human carcinogen
c Dust, prevent dispersion of dust; women, avoid exposure of (pregnant) women; all contact, avoid all
contact; children, avoid exposure of adolescents and children