WASHINGTON (AP) -- A bill pending in Congress that's named for an Oklahoma dog would make it illegal for middlemen to sell what are called "random source" cats and dogs to research labs.

The Humane Society of the United States estimates that every year the middlemen known as "Class B" animal dealers round up about 18,000 dogs and cats through flea markets and free-to-good-home ads, and then sell them to laboratories and university research labs.

In the process, the animal welfare group says lost pets are rounded up, too.

The proposed ban is dubbed "Buck's Bill" in honor of Buck, a black hound dog seized in 2003 in Oklahoma from a dealer. Buck, who had heartworm disease and other ailments, died of internal hemorrhaging months after his rescue, while in foster care.

Mary Hanley, the executive vice president of the National Association for Biomedical Research, says she sees no reason for the law change.

She says there may have been past abuses, but it's not the current reality. She says labs are required to keep documentation on where their research animals came from.