The overall aim of this research is to develop an efficient accident causative model for job hazards prevalent in an oil and gas facility operating onshore and offshore conurbation and estimate future accident expenditure in the system. A questionnaire survey was used based on the findings from the interviews and focus group discussions. Markovian model was developed using QM for Windows software. The possible types of the accident for a company operation onshore and offshore environment were investigated. It was found that oil and gas workers were exposed to different hazards despite the existing legislations enacted to impact on the provision of occupational health and safety in the industry. The accident types investigated include Road, Marine, helicopter, workplace, medical, attack, community invasion, and fire. Road transportation can be seen to be the most prevalent source of an accident followed by a workplace hazard. From the model developed using Markov analysis, it is evident that 99.8% of workers in the Trivial state (S_3) would transit to Terminal state (S_1); it was also noticed from the F matrix that it would take an average period of 4 years and eight months for this transition. However, it was observed that 99.8% of workers in Major state (S_2) would transmit to a terminal state (S_1) at an average period of 2 years as shown in the F matrix. It is therefore recommended that road leading to the inbound and outbound facilities of the company should be in an excellent condition; offshore workers must receive adequate training on survival at sea and helicopter underwater escape. Site workers must also be properly kitted with personal protective equipment to prevent workplace hazard.