* Refinery outage could cause disruption to Forties grade
* Strike prompted by alleged victimisation of worker
* Decision to be made by union on Monday or Tuesday
By Simon Falush
LONDON, Sept 27 (Reuters) - Workers at the 210,000barrel-per-day (bpd) oil refinery in Grangemouth, Scotland votedon Friday in favour of strike action, raising fears ofdisruption to North Sea oil supplies that could drive up thebenchmark oil price.
Steam from the Grangemouth refinery, owned by PetroIneos, powers the adjoining Kinneil terminal,which receives oil from a pipeline carrying North Sea Forties,one of the four crudes that underpins the Brent oil benchmark.
"It could be very bullish for Brent...due to the Kinneiltie-up with the refinery," one trader said.
A strike at the refinery in 2008 led to concerns about oilsupplies and queues at petrol stations around Scotland as wellas pushing gasoil futures to a record high.
Brent oil rose following the news on Friday,reversing direction from a fall earlier in the day.
Over 80 percent of the workers balloted voted in favour ofstrike action over operator Ineos's treatment of a unionorganiser and worker, Stephen Deans, who is at the centre of adisciplinary action, the union said on Friday.
A decision on the next steps for industrial action would betaken will be made after the weekend, Pat Rafferty, Scotland'sRegional Secretary told Reuters.
"We've clearly got a strong mandate. We're consulting without shop stewards and will notify the company on Monday orTuesday."
Ineos is investigating Deans over whether his politicalactivities with the Labour Party contravened company policy, andaccuses the union of interfering with its inquiry.
"Ineos will not be bullied by the union's behaviour. Therecannot be one rule for union officials and one rule for everyoneelse," said Calum MacLean, chairman of Ineos Petrochemicals UK.
Ineos said that the investigation into Deans will becompleted by Oct. 25.
The Forties pipeline was expected to load about 329,000 bpdin October.
A spokeswoman for BP, which operates Kinneil,confirmed that it relies on steam from Grangemouth but said shecould not comment on the impact of a possible strike.
Relations between the workforce and Ineos, already strainedby the investigation into Deans, were put under further pressureafter comments about the future of the chemical plant.
MacLean said last week the plant could close by 2017 unlessit cuts pension costs and got government support.
BP (BP.)