Unusually high humidity may be to blame for problems with paper ballots throughout Illinois during the primary election March 20, state election officials said Tuesday. The state experienced record-setting temperatures and unseasonably high humidity the day of the primary, apparently affecting the “hydroexpansivity” — the tendency of paper to expand when it absorbs moisture — of the paper ballots and rendering them difficult or impossible to feed into the ballot scanners at some precincts. The moisture caused the dimensions of the ballot to expand and be off slightly. “It is possible that the problem ballots were just so close to the limits of the acceptable width tolerance that the additional humidity alone was enough to put them out of tolerance,” according to a report by State Board of Elections officials who investigated the matter. In all, 26 Illinois voting jurisdictions had problems with the ballots. Some had just a few ballots that would not feed into the scanner, while at least one had difficulty with all of its ballots. Election judges chose to either trim the edges of the ballots so they would fit into the scanners or to remake the ballots on proper-width ballot stock.