(Portland, OR) -- A hard-to-reach brush fire took five hours to put out in Portland early Wednesday morning. The fire was burning on Hayden Island, west of the Interstate Bridge. Several locked gates and sandy soil made it difficult for fire engines to reach the area. A fire boat used turret water guns to put out most of the fire. Crews in specially equipped four-wheel-drive vehicles and ATV's reached the fire. There were no hydrants nearby, so water had to be shuttled to the scene in tenders. 20 firefighters were used to put out the fire. The investigation into the cause is ongoing.