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Tests on Washington Farm Workers Reveal Routine Pesticide Exposure
On February 8, 2005,
national and state farm worker organizations highlighted some very
disturbing medical monitoring results in Washington State. Their
report Messages from Monitoring looks at the first year of data
from a Washington State program that tests farm workers who regularly
handle organophosphates (OPs) and carbamates (CBs), both of which
are neurotoxic pesticides. The report shows that one in five workers
tested experiences significant inhibition of cholinesterase—an
enzyme essential to proper nervous system function—and faults
both state and federal agencies for failing to protect farm workers.
For nearly 20 years,
farm workers in Washington have pressed for a medical monitoring
program, similar to a program instituted in 1974 in California,
which has the only other monitoring program for this highly toxic
class of pesticides. After a state Supreme Court ruled in favor
of the farm workers, testing began in Washington at the start of
the 2004 growing season. The Washington program applies to all workers
who mix, load, apply or otherwise handle highly toxic OP or CB pesticides
for 50 or more hours a month.
When exposure to
OPs or CBs causes declines in cholinesterase levels, workers can
suffer serious health effects such as nausea, headaches, fatigue
and seizures. If levels decline further more severe and potentially
irreversible effects can occur, including long-term memory loss,
paralysis and death.
Workers receive
“baseline” blood tests prior to the spray season to
identify normal levels of cholinesterase. They then receive monthly
follow-up tests when they met or exceeded the 50-hour per month
handling threshold. (That threshold drops to 30 hours per month
in 2005.) Under the monitoring rules, when cholinesterase levels
decline by more than 20% from the workers’ baseline level,
employers are required to conduct workplace audits to identify and
address factors contributing to serious depression. When levels
decline by 30% or more in red blood cell tests or 40% or more in
blood plasma tests, workers must be removed from handling tasks
until their cholinesterase levels rebound sufficiently. Employers
can reassign workers to other tasks that do not involve significant
exposures if available, and must maintain full salaries and benefits
for removed workers.
Over the course
of the spray season, 123 (21%) pesticide handlers out of 580 who
received both baseline and follow-up tests had depressions of more
than 20% (the workplace audit level). Of these, 26 (over 4% of the
580 workers) had depressions low enough to trigger removal under
the state rules.
Four pesticides
were repeatedly involved in serious depressions: chlorpyrifos (Lorsban),
azinphos methyl (Guthion), carbaryl (Sevin) and formetanate (Carzol).
The majority of handlers needing removal for cholinesterase depressions
used a mixture of carbaryl and an OP insecticide (chlorpyrifos or
azinphos methyl). One common contributing factor at workplaces with
depressions was the use of air-blast sprayers towed by tractors
to apply the pesticides.
Significantly, in
a large percentage of the serious depression cases, there was no
evidence of non-compliance with federal Worker Protection Standards
or pesticide labels. Many case summaries, in fact, noted that growers
and their employees exceeded regulatory requirements by wearing
a respirator for chlorpyrifos though this is not required. The report
notes that EPA’s own analysis predicted that occupational
exposures would pose unacceptable risks, “In fact, citing
cost-benefit provisions in federal pesticide registration law, EPA
has approved continued use of some highly toxic OPs while openly
acknowledging that even with full Personal Protective Equipment
(PPE) and engineering controls, workers will experience exposures
which EPA considers unacceptable, i.e. having Margins of Exposure
(MOE) less than 100. Almost all handling scenarios for azinphos
methyl pose exposure risks for workers which EPA considers unacceptable,
and numerous scenarios for chlorpyrifos do the same.”
Messages from Monitoring
identifies serious problems in the Washington program that may mask
evidence of even greater harm. For example, statistical analysis
done by the program’s Scientific Advisory Committee reveals
the risks of false negatives may be as high as 50%. The Committee
also noted that many depressions might have been missed because
of the length of time that elapsed between sample collection and
analysis. In other cases, workers reportedly declined monitoring
due to actual or perceived employer interference.
The report also
faulted the Washington State Department of Labor and Industry (L&I)
for its slow response when testing revealed cholinesterase declines.
“L&I chose not to use its enforcement authorities to investigate
workplaces where depressions occurred. Even in cases where multiple
workers had depressions, the agency adopted a ‘consultation’
approach.” The average interval between receiving test results
and performing workplace audits or removals was more than seven
days, during which time the workers may have been receiving additional
exposures.
Messages from Monitoring
points out that the Washington monitoring program only tests pesticide
handlers, and not field workers—despite a growing body of
literature demonstrating routine pesticide exposure among field
workers and their families. Finally, the report faults government
for failing to promote alternatives to these dangerous pesticides,
and calls on state agencies and the federal government to end the
use of the most risky pesticides, including azinphos methyl, chlorpyrifos
and other highly toxic OPs and CBs, and to require cholinesterase
monitoring on a national basis.
The United Farm
Workers of America, AFL-CIO (UFW) is now circulating an online petition
asking EPA to implement a national cholinesterase monitoring program.
To sign the petition visit: http:/www.unionvoice.org/campaign/PesticideMonitoring.
Sources: Messages
from Monitoring, Farm Worker Pesticide Project, Farmworker Justice
Fund, United Farm Workers, http://www.fwjustice.org.
Contact: Farm
Worker Pesticide Project, 206-729-0498, PANNA.
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