(UPDATED COVERAGE, May 15) Shipments of apples and pears to Europe have slowed to a trickle after European Union regulations on a chemical treatment effectively cut off U.S. shipments.

While some organic fruit is being shipped to Europe, Christian Schlect, president of the Northwest Horticultural Council, Yakima, Wash., said most shippers have stopped because minimum residue regulations for diphenylamine — known as DPA — a chemical widely used to prevent scald developing on apples in storage.

Europe’s sharply reduced minimum residue level for DPA went into effect March 2, said Jeff Correa, international marketing director for Pear Bureau Northwest, Milwaukie, Ore.

U.S. and European trade officials are negotiating agricultural chemical issues, but a resolution could take a long time.

While DPA is used on apples, Correa said the chemical can cause residues on pears because most shippers run apples and pears across the same packing lines and put fruit in the same storage rooms.

Some pear-only shippers still plan to ship to Europe next year, he said.

Randy Steensma, president of Honey Bear Tree Fruit Co., Wenatchee, Wash., said that firm wasn’t shipping fruit to Europe.

“Right now we figured it was unworkable,” he said.

European Union minimum residue standards are so unforgiving that shipping fruit to the market is too risky, he said. If fruit is rejected upon arrival, the load must either be sent back to the U.S. or moved to a non-European Union country, Steensma said.

The DPA issue has been a knockout blow for trade, but Schlect said the European market for Northwest tree fruit has been declining in importance for several years. Factors such as competitive supply within Europe, strong buy-local sentiments, retail-specific minimum residue levels and European restrictions on certain types of wax have made it difficult to market apples and pears there, industry sources said.

U.S. apple exports to Europe sank from about 1.76 million (40-pound) boxes in 2009 to about 715,000 boxes in 2013, according to U.S. trade stats.

Correa said shipments of pears to Europe in the 2013-14 season totaled about 67,000 boxes, about 27% below the previous year. The European pear market used to be the third-largest export market for U.S. pears, at 400,000 boxes annually in the early 2000s, he said.

Schlect said the tree fruit industry would like to get Europe’s regulations on DPA revised.

“We want to at least get the European authorities to potentially take another look at it or to at least acknowledge that they are not rejecting it because of health reasons,” he said.

Schlect said the Environmental Working Group has seized on Europe’s action on DPA to draw attention to its Dirty Dozen list, which has apples sitting at the top spot. But Schlect and other industry leaders say the DMA issue is not about food safety.

“We haven’t given up and we are looking at trying to see what could be done,” he said.

Even if DPA is OK’d for use in Europe, Schlect said it will take a backseat to stronger demand from Asia and Latin America.