Air2Work has hired Kevin O'Connor, formerly of Scotland Electronics International, to take over the running of the Aberdeen business from Alan Brodie, who is moving into a non-executive director position.
The seven-figure investment in equipment will see it double its rental fleet of breathing systems to 30.
The company, owned by Norwegian firm E Innovation, also plans to hire two new staff and take its headcount in Scotland to eight.
Currently, it mainly operates in the North Sea but is targeting expansion into the US, Canada and Australia.
Mr O'Connor said: "The marketplace is continually growing and there are significant opportunities for Air2Work, particularly given the ageing nature of assets throughout the global oil and gas industry - both in terms of renovation and decommissioning.
"Major renovation programmes, as part of shutdown and turnaround operations, involve exposing energy-sector workers to hazardous conditions and our equipment provides them with guaranteed safe breathing air. We are seeing rising demand from asset maintenance contractors, with projects such as blasting and painting, tank cleaning and non-destructive testing campaigns, sandblasting and painting also involving specialists undertaking works in hazardous environment operations."