This research was conducted at an assembly section in a
battery manufacturing plant in Bangkok, Thailand. The
assembly section brings workers into stable contact with
lead during their daily work, such as assembling the plates,
mixture of lead oxide and sulfuric acid, to a battery cell,
putting the battery cell into the cell compartment of battery
case unit, sealing the poles of each cell, and closing the battery
cover. Thirty-one workers were engaged at the assembly
section in 2002.
Characteristics of workers were examined by an interview
using a questionnaire before occupational health education.
We checked knowledge on risk of contact with lead, behavior
for protection against toxicity of lead, and personal hygiene
by questionnaire before and after occupational health
education.
Occupational health education was provided as training to
all workers at the assembly section and managers of the factory
for 3 h at a time. Lectures focused on the toxicity of lead and
how to protect themselves from harmful properties of lead,
including route to exposure to lead, signs and symptoms of
lead poisoning, and personal hygiene. In addition,
demonstration of wearing an appropriate mask (3M, 9322),
fit testing and respiratory protection training were given as
training at a meeting room of the factory. These contents of
occupational health education are shown in Table 1.
As to the collaboration, the managers were asked by the
team of researchers after occupational health education to
continue supporting the workers to use personal protective
equipment at both the assembly section and other sections.
The managers permitted the workers to join in all steps of
this research. The workers willingly participated in this
research and collaborated with managers on that. However,
they were not obligated to use the mask (3M, 9322). They
could change the mask, if they found its decreased efficacy
or its defect.
The airborne lead level was measured by personal sampling
as follows. Two instruments for air sampling, (1) Personal
Gravimetric Pump (SKC, Aircheck samplers Model 224-
PCXR4) of which flow rate was adjusted to 2 L/min and
was calibrated by a calibrator (Gillian, Gillian Model
Gilibrator-2 serial No.705-0030) and (2) filter holder
containing a mixed cellulose ester membrane filter (diameter
37 mm, pore size 0.8 µm), were set together at breathing
zone level of workers at the assembly section. Twenty-two
samples were analyzed under NIOSH 71052).
The blood lead level was measured with 23 workers at
the assembly section before occupational health education
and with 26 workers 2 months after occupational health
education. It was performed under NIOSH 80033). Blood
sampling was conducted by trained examiners. Samples
were analyzed at the Department of Occupational Health
Laboratory, Ministry of Public Health, Thailand. To
minimized measurement errors, we selected the same
laboratory that we had asked to analyze the blood samples
since 1998.
Statistical analyses were conducted with SPSS for
Windows, version 9.0. Chi-square test was used to compare
the distributions of blood lead levels of workers before and
after occupational health education. A paired t-test was used
to compare the change in blood lead level before and after
occupational health education. The correlation between
airborne lead level (personal sampling) and difference in
blood lead level were evaluated with Pearson’s correlation.
Any P values less than 0.05 were considered statistically
significant.