Polls opened at 6 a.m. in New York City on Tuesday and long lines immediately started to form at many polling places. Voters across the city have reported waiting in lines for more than an hour, with many blaming broken or malfunctioning scanners, according to multiple tweets, voter texts sent to Electionland and tips sent to a national election hotline run by the Lawyer’s Committee for Civil Rights Under Law. The majority of such reports are coming from Brooklyn, Queens and the Bronx, but long lines and broken machines have also been reported in Manhattan.

“All but 2 machines are broken. Over 100 waiting on line already,” Carl Hamad-Lipscombe tweeted from his polling place in Midwood, Brooklyn. “Not what we’d expect in NYC. Hopefully I get to vote later, couldn’t wait another hour.” For many, these wait times are unprecedented and, they say, often double or triple the norm.

One of the reasons for the malfunctions, according to these accounts, are scanners getting jammed when voters try to scan their paper ballots. New York City’s ballot itself is part of the problem, it appears. This year, the ballot consists of two pages, each of which is double-sided, to accommodate city referendums listed on the back. The pages have thicker paper than in previous years, according to one expert, and need to be carefully torn along a perforated edge.

Michael Ryan, executive director of the New York City Board of Elections, said it’s impossible to say why the machines are jamming. He agreed that perforation or humidity could be a factor. Ryan also said that the rate of machine failure is consistent with the rate in other elections, but he noted that turnout is higher and every voter is scanning two pieces of paper. “This is a very positive thing that people are turning out to vote,” Ryan said. “With more volume, you’re going to have chokepoints.”

Ryan himself already seems the target of political heat. Early Tuesday afternoon, Corey Johnson, the speaker of the New York City Council, cited the voting problems and tweeted, “Michael Ryan should resign & we should begin a top to bottom review of how this happened. It’s time for new leadership at BOE.” Ryan did not immediately respond to a request for comment after Johnson’s tweet.

As the graphic indicates, complaints were widespread. At PS 22 in Brooklyn’s Prospect Heights neighborhood, voter Steve Swamy said, “All my polling station machines have shut down. … Now they are stuffing ballots in some emergency ballot box. It’s been a two-hour wait for most.” At Vladeck Hall, one of the largest polling sites in the Bronx, all four scanners were broken, Jack Marth and Kevin Dugo reported on Twitter.

Malfunctioning scanners typically do not prevent votes, said Joseph Lorenzo Hall, the chief technologist and director of the internet architecture project at the Center for Democracy & Technology, a Washington, D.C.-based nonprofit advocacy organization. “When a voting machine or scanner is nonfunctional,” he said, “people can still cast ballots.” The standard procedure is to put the ballots in an “auxiliary” or “emergency” slot on the scanner to be counted later when the machine is functioning again.

Susie Armitage, Carrie Brown, Rachel Glickhouse, Jessica Ramirez and Lakshmi Sivadas contributed to this report.