A global ban on trading and selling elephant ivory took effect 15 years ago, but a vibrant market for ivory remains in the U.S., and the Internet may be helping fuel it, a new study has found.

TRAFFIC, the wildlife trade monitoring network of the World Wildlife Fund, found that the “United States has the highest rate of ivory seizures in the world and that much of the ivory caught at the borders is being brought into the country by individual consumers, often as souvenirs, jewelry and carvings.”

“An average of about 1,000 items per week are advertised as elephant ivory offered for sale on eBay during TRAFFIC�s investigation,” the group said. “TRAFFIC found regular shipments of ivory carvings and jewelry being sold to U.S. customers over eBay from vendors in China under circumstances that may be illegal, with these web-based “stores” routinely shipping ivory to the U.S. via express delivery service and even offering to falsely label the shipments as containing bone.”