The 2015 report provides the offshore petroleum industry, its workforce and the wider community with key industry performance data that can be used as a benchmark, and despite the fact that injuries rose last year, the data provided by NOPSEMA appears to show that the offshore sector, while inherently dangerous, is continuing to keep its risks as low as possible.

In particular, after three consecutive years of increases, uncontrolled hydrocarbon releases decreased by 28% in 2015 compared to 2014. Environmental reportable incidents also reduced by 40% on the number reported in 2014.

"These results are encouraging as NOPSEMA has consistently called on industry to reduce the number and volume of uncontrolled hydrocarbon releases," NOPSEMA CEO Stuart Smith said.

The number of environmental management recordable incidents increased 17% over the last year, with a staggering 214% increase in solid waste discharge or dropped object, and a 72% spike in breached procedural control.

Four basic root causes were equally attributed to hydrocarbon releases in 2015 - design, equipment parts/defects, tolerable failure and preventive maintenance.

NOPSEMA received notification of 13 reportable environmental management incidents. The worst incidents were a discharge of around 12 barrels of oil on the North West Shelf when a hose coupling parted spilling 1900 litres of oil into the sea. Elsewhere, around 49 million cubic feet of gas was released when a facility flare was extinguished and flowed unlit for two minutes.

However, the data indicates that there are other areas of concern. There was a 49% increase in the number of injuries to the offshore workforce compared to 2014, with some 85 injuries were reported, ending a five-year downward trend.

Hours worked offshore also increased by 7%, from 14.3 million hours in 2014 to 15.3 million in 2015.

During the year some 366 dangerous occurrences were reported, which is comparable to the last few years, and some, up 49% from the year earlier.

While the oil patch was fatality free, NOPSEMA was notified of five serious injuries and seven LTI3 days.

"Whilst the majority of these injuries were medical treatment or alternative duties injuries, they are concerning none the less, and NOPSEMA will continue to monitor and inspect offshore facilities to ensure that the industry is making the safety of its workforce a top priority," Smith said.

There were also nine fires and one explosion reported, 70% of which were on drilling rigs, with no injuries.

But there were no accidents, dangerous occurrences or environmental incidents in 2015 that warranted NOPSEMA initiating a major investigation.

In 2015 NOPSEMA conducted 195 inspections, covering a total of 208 facilities, titles and petroleum activities, the highest number since the authority was formed in 2012, and 34% up on the year earlier.

There were 148 active facilities in 2015 run by 38 operators, the same as in 2014 but with a slight variation in facility types, with fewer rigs and platforms, replaced by a greater number of pipelines and FPSOs.

The regulator refused 23 safety cases of 102 submitted, four diving safety management systems and five well activity applications, two environmental plans of 44 submitted and one well operation plan.

The regulator followed through on two prosecutions, winning a $330,000 fine from Stena Drilling over the deaths of two workers while drilling the Geographe-3 development well for Origin Energy in 2011 and securing a $20,000 fine from Hammelmann when a Technip diver was seriously injured whilst using an underwater high pressure jetting gun made by the German firm in 2011 because Hammelmann had failed to provide operating instructions.

"The onus of improvement rests with industry and I expect strong and sustained leadership from industry to continue improving safety and environmental outcomes in all areas of its operations. Where industry is found to be non-compliant, NOPSEMA will not hesitate to take appropriate enforcement action to ensure a return to compliance," Smith said.

"NOPSEMA will continue to engage with our many stakeholders to ensure the highest levels of regulatory outcomes are achieved," he said.