The purpose of the present study was to evaluate the effect of a safety campaign implemented midway during the construction of the railway and road link across the Sound, Oresund, between Denmark and Sweden. The safety campaign was multi-faceted and aimed both at promoting positive attitudes towards safety and at the behavioural aspects of safety at work. The effect of the campaign was a 25% reduction of the number of injuries resulting from accidents, which did not completely fulfil the objective set by the site owner. This effect became only just statistically significant when heterogeneity of type of work before and after the campaign was taken into account. The modest effect of the safety campaign might be explained by the fact that the site, like any construction site, was a temporary workplace, where several contractors' had short-term project assignments. Apparently, the contractors working routines were not sufficiently affected by the safety campaign. Other factors, that might affect a safety campaign at a construction site, are discussed. (C) 2002 Elsevier Science Ltd. All rights reserved.