The Election Protection Coalition did not specify the number of precincts that they say are understaffed.
Allegheny County's election manager, Mark Wolocik, said Tuesday it is not unusual for an election board member to enlist extra help with clerical duties at a busy polling place.
Wolocik said he knows of only one district that called his office seeking permission to swear in volunteers.
Wolocik says he expects 75 percent turnout in heavily populated Allegheny County, slightly higher than turnout in recent presidential elections.
Polls are open in Pennsylvania until 8 p.m. Anyone in line at 8 p.m. will be able to vote.