Abstract

Background
Exposures leading to irritant-induced asthma (IIA) are poorly documented.

Methods
We retrospectively screened the medical records of patients with IIA diagnosed in an occupational medicine clinic during 2000–2018. We classified the cases into acute (onset after single exposure) and subacute (onset after multiple exposures) IIA. We analysed in detail, occupations, causative agents and their air levels in the workplace, exposure events and the root causes of high exposure.

Results
Altogether 69 patients were diagnosed with IIA, 30 with acute and 39 with subacute IIA. The most common occupational groups were industrial operators (n=23, 33%), metal and machinery workers (n=16, 11%) and construction workers (n=12, 8%). Among industrial operators significantly more cases had subacute IIA than acute IIA (p=0.002). Forty cases (57%) were attributable to some type of corrosive acidic or alkaline chemical. Acute IIA followed accidents at work in different types of occupation, while subacute IIA was typical among industrial operators performing their normal work tasks under poor work hygiene conditions. The most common root cause was lack of information or false guidance in acute IIA (n=11, 36%) and neglect of workplace hygiene measures in subacute IIA (n=29, 74%).

Conclusions
Accidents are the main causes of acute IIA, whereas subacute IIA can develop in normal work in risk trades with poor work hygiene. Airborne strong acids or bases seem to be the most important causative agents of acute and subacute IIA. The different risk profiles of acute and subacute IIA should be considered in the prevention and identification of the cases.

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Comments

Table 3 Causative agents of irritant-induced asthma Main groups of causative agents Acute N=30 Subacute N=39 Total N=69 (%) Acid aerosols or fumes 6 Sulfuric acid Hydrofluoric acid Nitric acid Hydrochloric acid Hydrochloric acid and sulfur dioxide 7 Sulfuric acid* and ammonium fluoride Sulfuric acid* and hydrogen sulfide Sulfuric acid*, sulfur dioxide and sulfur trioxide Hydrochloric acid Nitric acid 13 (19) Base aerosols or fumes 5 Ammonia Sodium hydroxide Black lye 4 Ammonia Sodium hydroxide Alkaline epoxy polyamine hardener and cleaning agent 9 (13) Mixtures of acid and base aerosols or fumes 3 Ammonia, sulfuric acid, hydrochloric acid, hydrofluoric acid, nitric acid Sodium hydroxide, potassium hydroxide, sulfuric acid, nitric acid 3 (4) Inorganic gases 3 Chlorine dioxide 3 Chlorine dioxide Chlorine dioxide and hydrogen sulfide Sulfur dioxide 6 (9) Oxidising agents 1 Ozone 1 Hydrogen peroxide 2 (3) Other chemicals 5 Formaldehyde† Glutaraldehyde† Hexamethylene diisocyanate† Naphthalene compounds Pyrethrin 1 Hexamethylene diisocyanate† 6 (9) Mixtures 6 Bitumen, solvents and their thermal degradation products Sodium hydroxide, sodium hypochlorite Combustion gas Thermal degradation of polyester paint Sulfuric acid, sodium hypochlorite, chlorine dioxide gas Nitric oxides, diesel exhaust, mixture of oil and water 12 Ammonia and hydrogen sulfide Ammonia, hydrogen sulfide and endotoxins Hydrogen sulfide, sulfur compounds, sodium hydroxide, chlorine dioxide Calcium oxide and hydrogen sulfide Rubber chemicals and their thermal degradation products Solvents and mine dust Formic acid, acetic acid, formaldehyde Thermal degradation of polyvinyl chloride-polyurethane fabrics Trifluoroacetic acid and acetonitrile 18 (26) Dusts 4 Calcium oxide Cement 4 Ash Calcium oxide and alkaline dusts Cement Sulfuric acid-containing titanium oxide powder 8 (12) Endotoxins 0 4 4 (

4/15/2021