CALVERTON, N.Y. (CBSNewYork)– Animal shelter employees in Long Island risked their lives to save trapped animals after a fire broke out just after dawn at a kennel.

Alexa Unger remembers being overcome as she opened the door to the kennel.

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“I was kind of hit in the face with this big cloud of black smoke. It almost looked like it was snowing, but the snow was black,” she told CBS2’s Jennifer McLogan. “There was soot everywhere, covering everything, swirling. A lot of the dogs that are barking every single morning weren’t barking anymore.”

Unger ran through the kennel toward the Peconic River and into the clinic screaming for help.

“Adreneline kicked in, you just do it. Parts of me said, ‘you shouldn’t go in there,'” Barbara Wansor, a veterinary technician, told CBS2.

Kent Animal Shelter is a nonprofit haven for cats and dogs awaiting adoption. The animals were helpless to escape from their closed cages as dense walls of smoke increased by the second.

“Black smoke was billowing out of the chimney. And the thing about animals, and humans as well, they can within the next 48 hours get pneumonia from the smoke,” Pamela Green, shelter director, said.

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The Riverhead Fire Department arrived on the scene to discover that the frantic employees had risked their health to carry each animal out one by one.

“It was just so crazy. Just bringing them up here, getting them water, putting them in cages, checking them out, making sure they were okay,” Jennifer Connor, a veterinary technician, recalled.

Humans and animals alike were transported to the hospital in ambulances for smoke inhalation treatment. Everyone is now recovered and back at the shelter.

“You just have that urgency to get those lives out of there. Animals in there that need to be saved,” Wansor said.

The shelter director is extremely grateful the kennel wasn’t filled with its usual 35 dogs. It took 25 minutes to save the 12 trapped animals.

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The Riverhead Fire Department said a faulty boiler is to blame.