P.E.I. farmers have dumped thousands of tonnes of wheat. (CBC)

The Canadian Food Inspection Agency cannot explain why a Halifax mill is applying new standards and telling P.E.I. farmers it can't buy much of their wheat.

Ron Arsenault, a program manager for Atlantic area with CFIA, told CBC News Wednesday the standards for levels of toxin from the fungus fusarium blight have not changed in 20 years or more, and he can't explain why Halifax-based Dover Mills is rejecting thousands of tonnes of grain grown on P.E.I.

"The bottom line is CFIA has not instructed the mills to refuse wheat, contrary to some of the reports," said Arsenault.

The CFIA standard for most food products is two parts per million, and one part per million for flour destined for infant food products. Farmers told CBC News last week that Dover Mills began this year applying the one part per million standard for all grain it is purchasing, leading to thousands of tonnes of grain simply being dumped in the field.

CBC News called Dover Mills late on Wednesday, and the company has not yet responded.