Rather little is known about the role of occupational safety climate in a broader organisational
context, its antecedents and the mechanisms for how it may impact safety outcomes. This
study used a prospective longitudinal multi-level study design to examine the cause and effect
relationships between psychosocial conditions, safety climate, and safety behaviour. Data
were collected by means of questionnaires from 289 employees in 43 units at four occasions
during a period of 21 months of the construction of a road tunnel. Data were analysed using
two approaches for modelling change; an autoregressive latent variable model and a multilevel
growth curve model. Results showed that individual perceptions of safety climate
exerted a causal effect on individual safety behaviour, but we also found some evidence of a
reversed relationship, where safety behaviour influenced safety climate. Furthermore, we
found that work unit average perceptions of safety climate predicted the growth of the
individual safety behaviour but this influence was mediated by the individual's perception of
the safety climate. The results also indicate that supportive psychosocial conditions within an
organisation influence individual safety perceptions but do not per se have an impact on safety
behaviour.