Introduction: In addition to inhalation and dermal exposure, also oral exposure is relevant in the workplace, even though this exposure route is most often neglected. In order to improve the understanding of occupational oral exposure, a systematic identification of mechanisms leading to inadvertent ingestion in the workplace is needed, including the transfer of chemicals and the contribution of aerosols.

Methods: A systematic literature search was conducted according to the PRISMA method including 5 databases and 9 institutional websites. Information from the included studies was extracted in concept matrices and further analyzed.

Results: Overall, 175 suitable publications were selected. Identified mechanisms leading to oral exposure were the transfer of chemicals, eg, from hands to mouth, and contributions from aerosols. Transfer influencing parameters were categorized as environmental, substance-specific, transfer pathway, surface, contact, or skin characteristics.

Discussion: Even though oral exposure was mainly investigated for children so far, similar mechanisms can lead to oral exposure in adults. Although the parameters characterizing the transfer of chemicals were identified and categorized, inconsistencies in nomenclature were identified, and correlations between parameters and transfer efficiencies often remained unclear.

Conclusions: The transfer of hazardous substances and the contribution of aerosols were identified as mechanisms of oral exposure. Transfer parameters and the interplay between particles from aerosols and oral exposure were discussed.

The complete article is published in the Journal "Annals of Work Exposures and Health" (2025).