MINNEAPOLIS (AP) - Officials at the University of Minnesota are worrying that the year-old Green Line of the city's light rail system will disrupt lab experiments.

Interference with the university's sensitive and expensive research equipment has been caused by water, debris and some animals that have crept into the light rail tracks through rail access boxes. University officials say researchers haven't reported actual impact on current experiments, but tests conducted during the Green Line's first year of operation have revealed higher than desired electromagnetic interference.

Reports say that continued interference could affect several nuclear magnetic resonance machines, which are used in drug research, and how they work.

About 100 labs and 300 pieces of equipment are situated along the light rail route.