PACIFIC GROVE, Calif. -

Humane officers with the SPCA for Monterey County say they rescued 20 cats and dogs from deplorable conditions at a Pacific Grove home Wednesday.

The small corner home was filled with feces, urine, piles of clothing and trash.

Eighteen dogs, including four very young puppies, were locked in three small back rooms and SPCA staff said "the overwhelming stench of ammonia from urine" made it difficult for humane officers to breath. It also burned their eyes. Two cats were also inside.

Beth Brookhouser, spokeswoman for the SPCA, says the conditions of the home were so toxic and unsafe that Pacific Grove Fire Department officials recommended the animal rescuers not return to the house without protective equipment.

"The stench of ammonia made it very difficult to breathe, eyes water immediately. It was definitely not a safe place for any person or pet to be," said Brookehouser.

The house, designated as a historic home by the Heritage Society of Pacific Grove, has since been declared uninhabitable.

The rescued animals are suffering from flea infestations, eye discharge, ear infections, dental problems, hair loss, overgrown nails and overall neglect. At least one dog had a toenail so overgrown that it had pierced the animal's foot pad. Many of the animals are underweight, many are not spayed or neutered and at least two dogs are pregnant.

"Imagine living in that filth just day in and day out, no way out of it and truly get themselves clean and breathe fresh air. It was awful," said Brookehouser.

The SPCA was assisted by members of the Pacific Grove Fire Department and the Pacific Grove Police Department, as well as the city of Monterey building inspector.

Humane Investigations officers from the SPCA are still working on the case and will likely turn it over to the Monterey County District Attorney with a recommendation of filing multiple charges against the resident.

This is the third major rescue for the SPCA this past month. Investigators said this case is the most extreme they have seen in years.

To see more images of the animals and the home they were taken from, click here.