ANNAPOLIS -- The Maryland Senate on Thursday passed a bill that would hold dog owners more accountable for their animals' bites. However, the Senate's passage means the bill is likely dead.

The bill would require dog owners to prove their animals aren't dangerous if they are sued for a dog bite. It stems from a 2012 ruling by the Maryland Court of Appeals that said pit bulls were "vicious and inherently dangerous" dogs. For that reason, their owners were liable if the animals bit someone. Other breeds were still held to the so-called "One Free Bite" doctrine where victims had to prove the dog had previously bitten somebody.

The bill passed the House in February, but the Senate changed it to require owners be held to a stricter standard of evidence to prove their dogs aren't vicious -- something the bill's House sponsor says is a nonstarter.

"The amendment makes it almost impossible for a dog owner to defend themselves in court," said sponsor Del. Luiz Simmons, D-Montgomery County.

The amendment requires owners prove clear and convincing evidence that their dog isn't dangerous. The only higher standard is "beyond a reasonable doubt," while the bill previously required owners prove the lesser "a preponderance of the evidence" standard.

Simmons blames the Senate sponsor, Montgomery County Democrat Brian Frosh, for allowing the amendment. Frosh, chairman of the powerful Senate Judicial Proceedings Committee who is considering a run for attorney general, voted against the amendment, which passed 7-4. But Simmons said Frosh should have done more to encourage others to vote against it.

"Do you know any committee chairperson in Annapolis who can't get five votes?" Simmons asked. "If he had spoke against it, asked two members of his committee to vote against the amendment, the amendment would have died."

Simmons said the amendment was brought by trial lawyers. Neither Frosh nor the Maryland Association for Justice -- the trial lawyer's lobby -- returned calls for comment as of Thursday evening.

The decision came in the 2009 case where a pit bull terrier escaped its pen and mauled a 10-year-old boy, cutting his femoral artery and almost killing him.