The market's expansion is fueling tension over whether the federal program should be governed by a strict interpretation of "organic" or broadened to include more products by allowing trace elements of non-organic substances. The argument is not over whether the non-organics pose a health threat, but whether they weaken the integrity of the federal organic label.

In response to complaints, the USDA inspector general's office has widened an investigation of whether products carrying the label meet national standards. The probe is also looking into the department's oversight of private certifiers who are hired by farmers and food producers and inspect products to determine whether they can use the label.