Tradesmen protest at Exxon's UK Fawley refinery

* Protesters fear workers could be treated unfairly

* German contractor may not use British industry terms

LONDON, June 27 (Reuters) - Local UK tradesmen demonstrated outside the entrance to Exxon Mobil's Fawley refinery on Wednesday to demand that contractors working on a plant overhaul in the months ahead employ workers under the terms of an industry agreement widely used in Britain.

Unite, the union organising the protest, said Exxon Mobil should subscribe to the terms of the National Agreement for the Engineering Construction Industry (NAECI) to prevent unfair treatment of workers.

The U.S. oil major aims to reconfigure the Fawley refinery and decommission one crude unit as well as planning works on a gasoline-making unit, the fluid catalytic cracker FCC.

Unite said refusal to adhere to NAECI terms could compromise safety at the site and that an increasing number of contractors were afraid union membership could reduce their chances of finding work at Fawley.

Germany's Voith Industrial Services, which recently won a contract to work on the FCC, has not said whether it will use NAECI terms to employ tradesmen, according to Unite.

Exxon Mobil said contractors were responsible for handling relations at the site.

"It is the responsibility of the Fawley Mechanical Joint Committee (FMJC) to handle engineering construction industrial relations matters at Fawley" Exxon Mobil said in a statement.

Voith said it would provide a statement later on Wednesday.

"We have been trying to get safety reps in place, but there is a fear among employees that if they become reps they will be blacklisted," said Malcolm Bonnett, a regional officer for Unite.

Exxon Mobil denied that the dispute had any relation to safety at the refinery.

"All work at Fawley is carried out to the highest standards, and nothing will ever be allowed to compromise those standards" Exxon said, adding that NAECI terms were widely used by British contractors working at Fawley.

The protest was scheduled to start outside the refinery gates at 0600 local time and include distribution of leaflets to advise workers of their employment rights during the day.