(UPDATED COVERAGE, 3:06 p.m., May 16) At least four shipments of Mexican limes bound for the U.S. have been rejected at the border after they tested positive for chemicals banned in the U.S. for limes, but volumes and prices had not been affected as of May 16.

Shipments contained the chemicals propargite or dimethoate, said Bret Erickson, president of the Mission-based Texas International Produce Association.

Limes are not on the Environmental Protection Agency’s approved exemption list for propargite, which is sold under the brand names Omite and Comite, or dimethoate. Loads that test positive must be destroyed or returned to the shipper.

Erickson said May 16 that volumes had not been affected by the rejected loads.

“It seems to be very limited,” he said.

Jeff Brechler, salesman for Edinburg, Texas-based J&D Produce, said May 16 none of J&D’s imports had been affected and he had not heard of loads being rejected.

In the week ending May 11, volumes were up over the same week the year before, and year-to-date volumes were comparable, according to the U.S. Department of Agriculture. Lime prices have held steady at $30 a box for 40-pound cartons of 110s since April 23, according to the USDA.

Oranges, grapefruit and lemons are on the exemption list. Because U.S. lime production is so low, chemical companies did not invest the resources to get limes put on the list, Erickson said.

Erickson said the chemicals are widely used for controlling pests, mainly mites, in Mexican citrus production.

The association was scheduled to host a conference call with importers May 14 to discuss the chemicals and rejected loads, but it was postponed. It will likely be held the week of May 20 or the week of 27, Erickson said.