A recent lawsuit filed against Nestle Purina PetCare Company is claiming that the popular "Beneful" dog food contains toxins that are poisoning and killing people's pets. The lawsuit claims that a chemical may have been found in "Beneful" that is related to previous dog food recalls.

The lawsuit, filed in California federal court earlier this month by pet owner Frank Lucido, alleges that thousands of dogs have become ill or died as a result of eating "Beneful" dry kibble dog food.

Lucido owned three dogs - a four-year-old German Shepherd, an eight-year-old English Bulldog and an 11-year-old Labrador - and began feeding them Beneful dog food a few months ago. Because of home renovations, the dogs were kept in three different houses, CNBC.com reports.

Soon, Lucido's German shepherd began losing hair, smelled strange, and wound up at the vet with symptoms "consistent with poisoning." A week later, his wife found their English Bulldog dead. An autopsy showed signs of internal bleeding in the stomach and lesions on the liver, symptoms eerily similar to the shepherd's, according to the lawsuit. Then their third dog also became ill.

"All these dogs are eating Beneful," explained Jeff Cereghino, one of the attorneys representing Lucido in the action. "And the dogs are all, for a variety of reasons, not in the same house. So you take away the automatic assumption that the neighbor didn't like the dogs or whatever. He was feeding them Beneful at the start of this, and one got sick and died, the other two were very ill. And then he started doing a little research, and he realized the causal link, at least in his mind, was the food."

Cereghino said he soon found a pattern with allegations against Purina Beneful dog food.

"We found a significant number of folks who were trying to draw exactly the same causal link. Thousands," he said; Cereghino found as many as 4,000 allegations of dogs being killed by the dry kibble dog food.

What could be behind these dogs falling ill? The lawsuit claims toxins are to blame, listing propylene glycol and mycotoxins as possibly harmful substances in the Beneful dog food.

But Purina maintains the type of propylene it uses is perfectly safe for consumption, saying on its website: "Propylene glycol is an FDA-approved food additive that's also in human foods like salad dressing and cake mix."

Propylene is same substance that caused the spiced whiskey Fireball to be recalled in Europe last fall.

But food grade propylene glycol has been approved by the Food and Drug Administration. It also hasn't been linked to toxicity, especially the type being alleged against Beneful.

Cereghino thinks mycotoxins are the real culprit. According to the Daily Beast, mycotoxins are essentially a toxic byproduct of mold - but they're also quite commonly found in breakfast cereal.

The chemicals have been related to dog food recalls in the past, but have not been confirmed as dangerous by any experiments so far.

Purina issued a statement in response to the lawsuit saying "there are no quality issues with Beneful."

"We believe the lawsuit is baseless, and we intend to vigorously defend ourselves and our brand," the statement read. "Beneful had two previous class action suits filed in recent years with similar baseless allegations, and both were dismissed by the courts."

The statement continued, "Like other pet foods, Beneful is occasionally the subject of social media-driven misinformation. On-line postings often contain false, unsupported and misleading allegations that cause undue concern and confusion for our Beneful customers."