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membrane problems related to flour dust and 12 participants reported having been diagnosed
with allergy to flour by a healthcare professional, the burden of suspected disease related to
exposure to flour dust and other ingredients is much higher. Thirty-four percent of higher-
exposure and 26% of lower-exposure group participants had work-related asthma symptoms,
yet only 14% of the higher-exposure group and 9% of the lower-exposure group were
taking asthma medicine. This suggests undiagnosed occupational asthma among employees.
In addition, 37% of participants reported symptoms of occupational allergic rhinitis.
Participants with atopy were significantly more likely to be sensitized to wheat and other
ingredients, consistent with past studies of bakery and food allergy.
Work-related asthma symptoms were significantly more common in participants sensitized to
flour dust, wheat, corn, or onion than in those who were not sensitized. In addition to baker’s
asthma, IgE-mediated asthma and other allergic disease due to corn, soybean, onion, garlic,
and paprika have been reported in the medical literature [Park and Nahm 1997; Schöll and
Jensen-Jarolim 2004; Cummings et al. 2010]. Sensitization to these allergens was common
among participants, regardless of exposure group.
Work-related episodes of coughing were common among participants, regardless of
sensitization, likely representing general irritation from dust. Prevalences of work-related
allergic rhinitis and rhinoconjunctivitis symptoms were also reported by more than 20% of
all participants, regardless of sensitization. Work-related irritation symptoms are reported in
the medical literature to be more common than allergic symptoms among employees exposed
to flour dust.
Inhalable wheat (r = 0.89) and inhalable soy (r = 0.79) were positively correlated with
the inhalable flour dust concentrations. Other studies have also documented significant
correlation between inhalable wheat and inhalable flour dust [Baatjies et al. 2010; Page et
al. 2010]. This supports the use of inhalable flour dust sampling for monitoring exposures
instead of the more complicated and expensive inhalable wheat sampling.
The preferred method to control flour dust exposures is through engineering controls.
The plant management implemented local exhaust ventilation, but it was inadequate and
exposures still remain high. We did not quantitatively evaluate the local exhaust ventilation
as part of this HHE, but we did note that some local exhaust ventilation units were not
connected and were not adequately controlling exposures. Until engineering controls are
documented to lower exposures below the ACGIH TLV, respiratory protection should be
worn throughout the plant.
The implementation of a respiratory protection program and the selection of respirators
should follow the OSHA respiratory protection standard [29 CFR 1910.134] and the
NIOSH respirator selection logic [NIOSH 2004]. Once engineering controls (i.e.,
ventilation changes) have been implemented, employees’ exposures should be reevaluated.
Once exposures have been reduced, the respiratory protection requirement should be
reassessed using the NIOSH respirator selection logic because some jobs may no longer
need respiratory protection and others may need lower levels of protection. For jobs that
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still require respiratory protection, task-based exposures should be evaluated to identify
specific tasks that require respirators and those that may not. This may also help to prioritize
engineering control recommendations.
Conclusions
Nearly all plant employees whom we sampled were overexposed to flour dust from the batter
mixes and breading dusts. Dust concentrations for all employees we sampled, except frozen
shipping and some receiving and line 6 employees, exceeded the ACGIH TLV for flour dust
during our evaluation. Lack of or inadequate ventilation controls and poor work practices
contributed to high flour dust exposures. Sensitization to flour dust, wheat, spices, and other
ingredients was highly prevalent. There were high prevalences of work-related asthma
symptoms, cough, and rhinoconjunctivitis among all employees. Our evaluation suggests that
some employees have undiagnosed occupational asthma.
Recommendations
On the basis of our findings, we recommend the actions listed below. We encourage the
poultry breading plant to use a labor-management health and safety committee or working
group to discuss our recommendations and develop an action plan. Those involved in the
work can best set priorities and assess the feasibility of our recommendations for the specific
situation at this poultry breading plant.
Our recommendations are based on an approach known as the hierarchy of controls
(Appendix C: Occupational Exposure Limits and Health Effects). This approach groups
actions by their likely effectiveness in reducing or removing hazards. In most cases, the
preferred approach is to eliminate hazardous materials or processes and install engineering
controls to reduce exposure or shield employees. Until such controls are in place, or if they
are not effective or feasible, administrative measures and personal protective equipment may
be needed.
Engineering Controls
Engineering controls reduce exposures to employees by removing the hazard from the
process or placing a barrier between the hazard and the employee. Engineering controls
are very effective at protecting employees without placing primary responsibility of
implementation on the employee.
1. Evaluate the local exhaust ventilation systems to determine if they can be altered to
lower dust exposures below the ACGIH TLV for flour dust. If the current systems
cannot achieve these specified limits, modify or replace the systems.
2. Use a pneumatic transfer system equipped with a bag dump station to transfer
powdered ingredients to the dispensing hoppers. The system should be equipped