http://www.cbc.ca/news/canada/windsor/story/2013/05/31/wdr-moore-tornado-relief-us-border.html

American officials will not allow the 20,000 kilograms of food, blankets and diapers into the country until every item on board is itemized in alphabetical order and has the country of origin of every product noted.

Dennis Sauve, the volunteer co-ordinator for Windsor Lifeline Outreach and the food bank co-ordinator at the Windsor Christian Fellowship, the two organizations that gathered the goods, said it's a "physical impossibility" to do the paperwork required in time to get the perishable food to Oklahoma before it spoils.

Because U.S. President Barack Obama hasn't declared Moore, Okla., tornado a disaster area, the 52-foot trailer of goods is considered a commercial shipment rather than humanitarian aid.