If there is a flammable gas escape which could be ingested into the gas turbine combustion air inlet then the gas turbine could burn this fuel and control would be lost. The turbine could overspeed and be destroyed. Closing the fuel valve to the turbine may not stop the turbine in this situation.
Hopefully gas detectors in the combustion air inlet will detect the gas early enough to allow the gas turbine to be stopped.
I do not think that this is covered by a standard, it's a matter of risk assessment and design. More of a concern on petrochemical sites than on other industrial sites.
It might be covered in a specification issued by a petrochemical contractor.
This could also happen with reciprocating engines as well. I heard of a case where the was a leak of lubricating oil from a turbocharger, into the air inlet, which was not noticed. When they tried to stop the engine, it continued to run, with the diesel fuel shut off. I assume that the engine stopped when the lube oil was used up and the engine seized…