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3-(Bromomethyl)-2-chloro-4-(methylsulfonyl)- benzoic acid: a new cause of sensitiser induced occupational asthma, rhinitis and urticaria
  1. Hille Suojalehto1,
  2. Kirsi Karvala1,
  3. Saana Ahonen1,2,
  4. Katriina Ylinen3,
  5. Liisa Airaksinen1,
  6. Katri Suuronen1,
  7. Sari Suomela1,
  8. Irmeli Lindström1
  1. 1 Occupational Medicine, Finnish Institute of Occupational Health, Helsinki, Finland
  2. 2 Occupational Health Helsinki, Helsinki, Finland
  3. 3 Work Environment Laboratories, Finnish Institute of Occupational Health, Helsinki, Finland
  1. Correspondence to Dr Hille Suojalehto, Occupational Medicine, Finnish Institute of Occupational Health, Helsinki FI-00251, Finland; hille.suojalehto{at}


Objectives 3-(Bromomethyl)−2-chloro-4-(methylsulfonyl)-benzoic acid (BCMBA) has not previously been identified as a respiratory sensitiser. We detected two cases who presented respiratory and urticaria symptoms related to BCMBA and had positive skin prick tests to the agent. Subsequently, we conducted outbreak investigations at the BCMBA-producing factory and performed clinical examinations to confirm occupational diseases.

Methods The outbreak investigations included observations of work processes, assessment of exposure, a medical survey with a questionnaire and skin prick tests with 0.5% BCMBA water solution on 85 exposed workers and 9 unexposed workers. We used specific inhalation or nasal challenge and open skin application test to investigate BCMBA-related occupational asthma, rhinitis and contact urticaria.

Results We identified nine workers with respiratory and/or skin symptoms and positive skin prick tests to BCMBA in a chemical factory. A survey among chemical factory workers indicated a BCMBA-related sensitisation rate of 8% among all exposed workers; the rate was highest (25%) among production workers in the production hall. Sensitisation was detected only in workers with the estimated highest exposure levels. Six cases of occupational asthma, rhinitis and/or contact urticaria caused by BCMBA were confirmed with challenge tests. Asthma-provoking doses in specific inhalation challenges were very low (0.03% or 0.3% BCMBA in lactose).

Conclusions We identified a new low molecular weight agent causing occupational asthma, rhinitis and contact urticaria. A typical clinical picture of allergic diseases and positive skin prick tests suggest underlying IgE-mediated disease mechanisms. Stringent exposure control measures are needed in order to prevent BCMBA-related diseases.

  • cas 120100-05-2
  • contact urticaria
  • low molecular weight agent
  • occupational asthma
  • occupational rhinitis

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  • Contributors All authors participated in conception, design and interpretation of data and approved the final version. HS, KY, LA, SS and IL acquired data, HS and SA analysed data and HS drafted the article, which all authors reviewed.

  • Funding The study was entirely funded by the unit performing the study.

  • Competing interests None declared.

  • Patient consent Obtained.

  • Ethics approval The study was approved by the ethics committee of Helsinki University Central Hospital (approval number 403/13/03/00/15). All the participants signed an informed consentform.

  • Provenance and peer review Not commissioned; externally peer reviewed.