WEL Substance Profile

Flour Dust — Workplace Exposure Limit Change

CAS: Not applicable (natural material) | Notation: Inhalable fraction, respiratory sensitiser (RSEN)

Current WES

mg/m³

New WEL (Dec 2026)

0.5

mg/m³

Change

-87.5%

reduction

Health Effects

Flour dust is a potent respiratory sensitiser and the primary cause of baker's asthma, one of the most common forms of occupational asthma in developed countries. Sensitisation develops after repeated inhalation of flour proteins, particularly wheat alpha-amylase allergens, and is irreversible once established. Sensitised workers experience asthmatic symptoms including wheezing, chest tightness, coughing, and shortness of breath upon any subsequent flour dust exposure. Flour dust also causes occupational rhinitis, with symptoms of nasal congestion, sneezing, and rhinorrhoea often preceding the onset of asthma by months or years. Conjunctivitis from eye exposure is common. Chronic exposure to high concentrations causes progressive decline in lung function even in workers who do not develop sensitisation. Dermatitis from direct skin contact with flour and dough additives adds to the occupational health burden in bakery environments.

Where Exposure Occurs

Commercial and industrial bakeries during mixing and handlingFlour milling and grain processing operationsPizza and pasta manufacturing facilitiesSupermarket in-store bakeriesAnimal feed manufacturing using grain productsConfectionery manufacturing involving flour handling

What to Do Now

01Conduct baseline inhalable dust air monitoring at all flour handling workstations including mixing areas, dough preparation stations, flour storage and transfer points, and packaging lines. The 87.5 per cent reduction from 4 to 0.5 mg/m³ means that most bakery operations will need fundamental changes to dust control strategies. Use an IOM inhalable sampler for accurate measurement of the flour dust fraction that causes sensitisation.

02Install or upgrade local exhaust ventilation at all flour dust emission points. Enclosed mixing bowls with integrated extraction, dust-tight flour transfer systems, and dedicated extraction at bag-opening stations are effective engineering controls. Open-top mixers and manual flour scooping generate the highest exposures and should be replaced with enclosed systems where practicable.

03Implement closed flour handling systems. Bulk flour delivery via pneumatic transfer from silo to mixer eliminates bag-opening exposure entirely. For operations that continue to use bagged flour, bag-dump stations with integrated extraction and dust containment reduce exposure by 80 to 90 per cent compared to manual bag opening and pouring.

04Establish a respiratory sensitiser health surveillance program for all flour-exposed workers. Baseline lung function testing and symptom questionnaires must be completed before exposure commences. Periodic monitoring at intervals of no more than 12 months should include spirometry, symptom questionnaire, and skin prick testing for flour allergens where available. Workers who develop rhinitis symptoms should receive immediate assessment.

05Review housekeeping procedures to eliminate secondary flour dust exposure. Dry sweeping and compressed air cleaning must be replaced with HEPA-filtered vacuum cleaning and wet wiping. Flour spillage must be cleaned immediately using enclosed methods. Work clothing contaminated with flour dust should be changed at the end of each shift to prevent ongoing dermal exposure and cross-contamination of non-work areas.

Monitoring Method

Personal air sampling using a calibrated pump at 2 L/min with an IOM inhalable sampler and pre-weighed glass fibre or PVC filter. Gravimetric analysis for total inhalable dust. Where allergen-specific quantification is required, enzyme-linked immunosorbent assay (ELISA) for wheat alpha-amylase can be performed on the same filter extract.

Prepare Your Bakery for the 87.5% Limit Reduction

EHS Atlas tracks flour dust monitoring data against the incoming 0.5 mg/m³ WEL and manages health surveillance for respiratory sensitiser exposure in bakery operations.