A number of fire stations rely on part-time, retained firefighters
Scotland's fire service is under threat from EU working hours regulations, according to a senior fire officer.
MEPs have been criticised for voting to end the UK "opt out" of the Working Time Directive, which prevents people from working more than 48 hours a week.
Grampian Chief Fire Officer David Dalziel said the rules would prevent fire stations using retained staff.
In Scotland, most fire stations are staffed by part-time fire fighters who have other jobs.
Mr Dalziel said restrictions on how long people can work could spell the end of the retained service and jeopardise safety.
It would also have a huge cost implication with budgets soaring to pay for more full-time staff, he claimed.
The Fire Brigades Unions claimed Mr Dalziel was "scaremongering".
Scotland's chief fire officers are to lobby the government and MEPs over their concerns.
Orkney and Shetland MP Alistair Carmichael said 321 of Scotland's 391 fire stations were staffed by part-time retained fire fighters.
"A strict application of the directive will mean that they may often be left unable to provide the necessary cover", he said.
"The stark fact is that in many of our remoter communities we simply don't have the critical mass of population that is required to maintain a full-time service.
"Surely it is wrong that the law of unintended consequences should be allowed to leave some communities without effective fire cover in this way."
A final decision on ending the opt-out will be made by a European Union conciliation committee.
The EU working time directives could come in to effect in the UK in three years' time if they back the move.
Coastguards and the RNLI will also assess the implications.