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Ramps have also reopened, and traffic is flowing on Tuesday night. Northern Indiana Public Service Company crews were still making repairs late, but that gas line, which the company said was ruptured by a third party, has been capped off.
The natural gas mixed with gravel and dirt spewed from the ground, snarling traffic for hours and causing headaches and disruption.
"It is some of the worst traffic I've ever seen before. It was. It was. And you didn't know why," said Glenn Penick, who was stuck in the I-94 backup.
Officials said around midday, a contractor unaffiliated with NIPSCO ruptured a gas line near the Ameriplex industrial park along I-94 in Portage.
"I start vacation tomorrow. I was coming to turn in my old uniforms," said MCP USA employee Erc T. Barber. "I smelled the gas when I got to 12 and 20, and I saw all the traffic. I was like, 'What's going on?'"
The rupture prompted an afternoon-long shut down of the interstate in both directions between state roads 249 and 49.
"It's a combustible gas, and obviously, if somebody is driving down the highway, and there's a spark or whatnot, I think that was the concern with it igniting, because it was so close," said Portage Police Department Chief Mike Canadiano.
Around 40 employees of Tosca, a packaging company near the scene of the leak, had to be evacuated.
"We got evacuated about 12:30 p.m. They decided they gonna send everybody home, because there was gas that was starting to go into the building, and you could smell it," said evacuated worker J.H. Sizemore.
Shortly after 6 p.m., NIPSCO managed to cap the leak, allowing traffic in all lanes of I-94 to reopen.
But for many drivers, the day was already ruined.
"It's been frustrating, but hey, this is Chicagoland. You know, anything is possible," Penick said.
Portage officials say they have been told by NIPSCO that air quality was being monitored in the area, and there is no danger to nearby residents.
Indiana State Police said no injuries have been reported.