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Results
First Site Visit
Previous sampling by the plant found employee exposures to total dust (comprised mainly
of flour) at concentrations that exceeded the OSHA PEL of 15 mg/m
3
for particulates not
otherwise regulated.
In addition to flour dust, other ingredients used in the plant have been
reported in the medical literature to cause asthma including garlic, onion, soy, and corn.
Spicy flour used in the plant contained paprika and capsaicin, which can cause mucous
membrane and respiratory irritation.
Our review of the OSHA Logs revealed one employee diagnosed with baker’s asthma in 2005.
We interviewed 47 of more than 400 production employees. Twelve of the 47 were identified
from a list provided by the union of 18 employees who had reported work-related symptoms;
the other six on the union list were not at work at the time of our visit. The remaining 35
interviewed employees were serially selected from job categories with the greatest potential
for flour dust exposure. Twenty-five reported no work-related symptoms. Of the remaining 22,
six reported using an inhaler for work-related respiratory symptoms, and four reported being
Table 1. Employee exposure groups*
Lower exposure
Higher exposure
Clerk in office
Bread and batter
Fork lift operator
Lay-on
Bagger
operators
Oven operators
Trash dock and trash removal
Marination
Receiving employees
Foremax operators
Scale operators
Line leader
Box makers
Quality assurance
technicians
Frozen shipping employees
Bone checker
Tub washers
Utility
Temperature checkers
Checker/sorter
Stackers
Quality assurance production and
support
Packers
Cups
Warehouse ingredient handlers
Graders
Pallet jack operators
*Employees were classified on the basis of a review of work
processes, historical sampling data, and the professional
judgment of NIOSH investigators.
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Health Hazard Evaluation Report 2009-0131-3171
diagnosed with breathing problems due to flour dust. Eleven of these 22 employees reported
work-related shortness of breath, 10 reported work-related cough, 9 reported work-related
nasal symptoms, 8 reported work-related sneezing, 6 reported work-related eye symptoms,
5 reported work-related wheezing, and 3 reported work-related chest tightness.
Second site visit
We collected 100 personal breathing zone air samples throughout the plant. Table 2
summarizes the air sampling results for inhalable flour dust, wheat, and soy by exposure
group. Tables A1–A3 in Appendix A list these personal breathing zone results by the job
category observed on the day of sampling. Median airborne inhalable flour dust, wheat,
and soy concentrations were higher for the higher-exposure group than the lower-exposure
group, but there was overlap, and exposures were documented in all areas of the plant (Table
2). Concentrations of inhalable wheat (r = 0.89, P < 0.01) and soy (r = 0.79, P < 0.01) were
positively correlated with the inhalable flour dust concentrations.
Of 402 employees present during the site visit, 375 (93%) completed the questionnaire. Of
these, 242 (64%) allowed their blood to be drawn.
Table 3 lists the prevalences of work-related symptoms comparing the higher-exposure
group to the lower-exposure group, showing both the statistically significant (bolded) and the
nonsignificant differences. Participants in the higher-exposure group were significantly more
likely to report episodes of coughing, rhinitis symptoms, and rhinoconjunctivitis symptoms
in the last 12 months than lower-exposure participants. Table 4 lists the prevalences of work-
related symptoms comparing those currently in the higher-exposure group and those who
previously held jobs in the higher-exposure group to the lower-exposure group, showing
both the statistically significant (bolded) and the nonsignificant differences. Participants
Table 2. Summary of air sampling results by exposure group as
observed on the day of sampling
Higher-exposure
group
Lower-exposure
group
# of PBZ samples
65
35
Inhalable flour dust
Median
8.21 mg/m
3
1.03 mg/m
3
Range
0.59 to 93 mg/m
3
0.22 to 15 mg/m
3
Inhalable wheat
Median
0.188 mg/m
3
0.00321 mg/m
3
Range
ND to 1.8 mg/m
3
ND to 0.44 mg/m
3
Inhalable soy
Median
0.341 µg/m
3
ND
Range
ND to 7.2 µg/m
3
ND to 0.32 µg/m
3
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Health Hazard Evaluation Report 2009-0131-3171
either currently in the higher-exposure group or who had previously held jobs in that group
were significantly more likely to report asthma symptoms in the last 12 months, including
wheezing or whistling in the chest and attacks of asthma, than employees in the lower-
exposure group.
Of the 244 participants who reported having held other jobs at the plant, 45 reported having
changed jobs for health reasons. Significantly more participants reported changing jobs for
health reasons in the lower-exposure group than in the higher-exposure group (24% vs. 12%,
P = 0.01). Twenty-three participants reported changing jobs because of respiratory tract or
mucous membrane problems. Twelve of 375 participants reported having been diagnosed by
a healthcare professional with allergy to flour.
Table 3. Prevalence of work-related symptoms in the last 12 months* by current exposure group
Work-related symptom
Higher-
exposure group
n=158–161†
Number (%)
Lower-exposure
group
n=212–213†
Number (%)
Prevalence ratio
(95% confidence
interval)
Episodes of coughing
43 (27)
39 (18)
1.46 (1.00, 2.15)‡
Asthma symptoms§
54 (34)
55 (26)
1.29 (0.94, 1.77)‡
Wheezing or whistling in chest
41 (25)
32 (15)
1.69 (1.12, 2.58)‡
Woken up with feeling of tightness in
the chest
24 (15)
22 (10)
1.42 (0.83, 2.46)‡
Attack of asthma
11 (7)
12 (6)
1.24 (0.55, 2.76)‡
Currently taking medicine for breathing
problems or asthma
22 (14)
19 (9)
1.53 (0.86, 2.77)‡
Rhinitis symptoms
Problem with sneezing or a runny
nose or a blocked nose when did not
have a cold or flu
71 (44)
65 (31)
1.45 (1.11, 1.90)
Rhinoconjunctivitis symptoms
Rhinitis symptoms accompanied by
itchy watery eyes
51 (32)
46 (22)
1.49 (1.06, 2.10)
*Or since beginning current job if in that job for less than 12 months
†Denominators vary because of missing information
‡Controlled for smoking status
§Work-related asthma symptoms based upon a positive answer to one or more of four questions
below it in table