Asbestos Fibers and Other Elongate Mineral Particles: State of the ...

States, includes a discrete code for malignant
mesothelioma. Based on that new ICD-10 code,
the age-adjusted death rates (per million population)
for 1999–2004 were 12.9 (based on 5
mesothelioma deaths) for Jefferson County and
10.9 (based on 5 mesothelioma deaths) for St.
Lawrence County. These are similar to the overall
U.S. mesothelioma death rates for this same
period (based on a total of 15,379 mesothelioma
deaths) of 11.5 per million [NIOSH 2007b].
An excess of lung cancer has also been reported
following several epidemiological studies
of New York talc mines and mills [Kleinfeld et
al. 1967, 1974; Brown et al. 1990; Lamm and
Starr 1988; Stille and Tabershaw 1982; Lamm
et al. 1988; Honda et al. 2002]. The most extensive
research has been conducted on workers
at the talc mine and mills owned by RT
Vanderbilt Company, Inc. (RTV), located in St.
Lawrence County. A significant excess of mortality
from nonmalignant respiratory disease
(NMRD) has been consistently noted in these
studies. These studies have also generally demonstrated
an approximately twofold to threefold
increase in lung cancer mortality among
these workers [Brown et al. 1990; Honda et al.
2002; Lamm et al. 1988]. The lung cancer excess
has been reported to be particularly high
among workers with more than 20 years since
their first exposure (latency), which is a pattern
consistent with an occupational etiology
[Brown et al. 1979, 1990]. Authors of several
studies have questioned whether the excess of
lung cancer observed in these studies is due to
employment at the RTV mines and mills or to
other factors [Honda et al. 2002; Lamm et al.
1988; Stille and Tabershaw 1982]. Attributing
these findings to employment in the RTV mine
is difficult because there were numerous mines
operating in upstate New York, and the mineralogical
composition of the ores varied substantially
[Petersen et al. 1993]. A high smoking
22
rate among the workers at the RTV mine and
mills has been suggested as one possible explanation
for the excess lung cancer mortality
[Kelse 2005; Gamble 1993]. However, it is generally
considered implausible that confounding
by smoking in occupational cohort studies
could explain such a large (i.e., about twofold
to threefold) increase in lung cancer mortality
[Steenland et al. 1984; Axelson and Steenland
1988; Axelson 1989].
The most persuasive argument against a causal
interpretation of these findings is that the
lung cancer excess in this study population did
not increase with duration and measures of exposure
to dust [Lamm et al. 1988; Stille and
Tabershaw 1982; Honda et al. 2002]. Also, the
excess of lung cancer in this cohort has been
reported to be limited to workers with short
employment (