A now extensive body of international research has pointed to an association between changing work arrangements, especially those commonly labeled as precarious employment or contingent work with serious adverse occupational health and safety (OHS) outcomes. There is also a growing body of research pointing to how these work arrangements have weakened or bypassed existing OHS and workers' compensation regulatory regimes - and responses to this. However, there has been little or no systematic research into awareness and perceptions of such issues amongst OHS inspectors, and how they address them when they undertake workplace visits or investigations. Between 2003 and 2007 we were involved in an Australian Research Council funded project that entailed detailed documentary and statistical analysis, extended interviews with 170 regulatory managers and inspectors, together with observational data collected while accompanying inspectors on 118 'typical' workplace visits. Key findings are that inspectors responsible for a range of industries see altered work arrangements as a serious challenge, especially labour hire and subcontracting. Though the law imposes clear obligations, inspectors identified misunderstanding/blame shifting and poor compliance amongst parties to these arrangements, and the complexity of work arrangements, as increasing the inspection and enforcement challenges faced by inspectorates.