An undercover investigation by animal welfare activists found that the sale of undocumented elephant ivory is still "thriving" in Massachusetts despite efforts made by several other states to ban the sales.
The investigation found several elephant ivory items for sale in May by five vendors at the New Bedford Whaling Museum's annual nautical antiques show, according to a report by the Humane Society of the United States.
The items included ivory canisters, canes with handles made of ivory, a wood and elephant pocket watch stand, small trinkets made of ivory, including miniature ivory dollhouse furniture and other assortments of small elephant ivory tools and other pieces, according to the report.
The sellers were unable to produce documentation verifying the age and origin of ivory, which is necessary to determine whether they were imported in violation of federal law.
During a previous investigation, a seller in Massachusetts offered tips for smuggling ivory out of the country, telling the undercover investigator that Chinese citizens buy ivory items at the antiques show and ship them back to China, according to the report. The employee said it was "not a problem" if the items were packed in a suitcase and were not disclosed to customs agents, the report said.
A spokeswoman for the New Bedford Whaling Museum did not immediately respond to ABC News' request for comment.
In 2015, an investigative report by The Boston Globe found that illegal operators in Massachusetts were participating in "brisk trade" of illicit ivory.
The state currently does not have a law in place prohibiting the intrastate trading of ivory or rhino horn, but the Massachusetts State House will hear public testimony on Tuesday regarding legislation that would implement a ban: Senate Bill 496 and House Bill 772, filed by Sen. Jason Lewis and Rep. Lori Ehrlich.
Ten states, including New York, New Jersey, California, Hawaii, Oregon, Washington, Nevada, New Hampshire, Illinois and Minnesota have implemented similar laws in recent years.
"The trade in ivory contributes greatly to a devastating decline in elephant populations," said Kitty Block, president and CEO of the Humane Society of the United States, in a statement. "I am deeply saddened that ivory sales are occurring right here in my home state of Massachusetts, and that the New Bedford Whaling Museum would host an event where ivory is being sold at all—particularly without apparent authentication that is required by our federal government."
Between 2010 and 2012, 100,000 elephants were killed for their ivory, according to Ivory Free Massachusetts.
The U.S. is among the largest markets for illegal wildlife goods in the world, according to the Humane Society. Enforcement efforts are often hampered by lack of resources and the difficulty of distinguishing illegal ivory from legally acquired ivory.
The Endangered Species Act of 1973 prohibits the importing, exporting and interstate transport and sale of items involving endangered and threatened species in the course of commercial activity.
A near-total ban on commercial trade of ivory went into effect on July 6, 2016. Ivory can only be sold out of state if it's more than 100 years old or is part of a manufactured product, such as a musical instrument, according to the U.S. Fish and Wildlife Service. However, the ban does not affect commerce within states.
In July, the Humane Society announced the findings of a "lucrative" ivory trade in Washington, D.C., where "ivory dealers take advantage of the lack of local laws banning the sale of ivory."
Legislation has been introduced in the Council of the District of Columbia that would prohibit sales of certain ivory products and products made from rhino horn, according to the organization.