Australia is striving to develop an offshore blue economy that meets needs for sustainable food production and renewable energy. Offshore aquaculture and wind farming is nascent in Australia, so we have little past experience to draw on for risk assessments. Risk assessments for offshore industries also need to consider hazards and opportunities across multiple sectors including aquaculture, environment, the economy, renewable energy, engineering and society. We developed an efficient method for integrated hazard analysis for emerging industries. We worked with 48 experts to create conceptual models of interactions in offshore systems. We used conceptual models to identify hazards and opportunities for each offshore sector. Experts then ranked hazards by importance. Many hazards were highly ranked across multiple sectors, showing shared concerns in sectors that are often perceived to be at odds to each other. Climate Change was the hazard with the overall highest concern, but Altered Ecosystem Function, Biosecurity, Cumulative Effects, Structural Failure and Social License were also highly ranked. Our approach can be used to identify hazards that can be retired or should be progressed to quantitative risk assessment. Government and industry policies that jointly address the most important hazards could benefit a broad range of sectors.