Compliance with hygiene and other safety measures in the workplace was an important component of society's strategy for reducing infections at the onset of the COVID-19 pandemic, in particular before vaccinations were widely available. We report the results of a field trial of well-established behavioural interventions (social norms, pledging and messenger effects) we implemented to improve compliance with such measures in an occupational setting. We use daily reports of own and other's behaviour to assess the effects of these interventions and supplement these subjective (self-reported) measures with objective data on hand sanitiser usage. The behavioural interventions tested have statistically significant but quantitatively moderate effects on subjective compliance measures and minimal effects on hand sanitiser usage. All effects of our interventions are short-term in nature and dissipate shortly after implementation. Our findings thus provide at most weak support for the notion that typical behavioural interventions can help support compliance with infection prevention measures in the workplace.