The largest homeless shelter in the city took in about 800 people overnight Tuesday into Wednesday.

Pacific Garden Mission, 1458 S. Canal St., normally doesn’t accept short-term visitors, but tossed protocol out the window this week to save lives.

“There’s no restrictions right now. We’re letting everybody in,” Pacific Garden Mission President Philip Kwiatkowski told the Sun-Times Wednesday morning.

“We’re putting mattresses on the floor. It’s a mass of humanity.”

Overnight lows were in the negative teens, and plunged to minus-23 degrees just before 7 a.m. at O’Hare International Airport.

Under normal circumstances, Pacific Garden houses people in 30-day increments, after which progress toward an independent life must be shown in order to extend a stay.

“I was out there for three or four days,” Alfred Harris Brown, 67, told the Sun-Times during a chat at the Pacific Garden Mission Wednesday. “My hands froze like nobody’s business, they were hurting … I appreciate this shelter, that’s the truth. I’m here and I’m warm.”

It’s unclear how many people sought warmth at shelters, libraries, warming buses provided by the Chicago Transit Authority and other public spaces during the current cold snap, which set in Tuesday.

City officials were trying to compile information Wednesday morning.

“What I can tell you right now is they’re being used,” Rich Guidice, who heads up the city’s Office of Emergency Management and Communications.

Harbor Light, a Salvation Army drug treatment facility at 825 S. Christiana, also transformed itself into a short-term shelter.

Salvation Army outreach workers contacted 40 homeless people in the area over the last few days but only five chose to stay at the facility Tuesday night, Salvation Army spokeswoman Nancy Powers told the Sun-Times Wednesday.

Each was greeted with a warm cookie and a welcome note on their cot.

“It’s kind of easy to form relationships when you hand someone a warm cookie when they come through the door,” Powers said.

A total of 100 cots are available, she said.