(Corvallis, OR) -- Smart meters on power grids could be a way for hackers to attack the system. Oregon State University researchers have found that hackers could use several meters to turn power off and on creating an oscillation that could trip circuit breakers causing a blackout. They say the study shows a vulnerability that can now be fixed by grid operators to prevent a possible attack. They could monitor for the oscillation and turn power off to areas before the it causes a blackout. They could also vary power generation sources which would limit the impact of an attack.