The reason is that the primary means by which the agency is able to do its control work is through export declarations. Export declarations are not required for goods to the United States other than in certain cases where certain permits are required. That is because the system was set up based again on export statistics rather than on risk assessment. We have an agreement with the United States that says we'll use their import data as our export data. That means that we don't get declarations, and that is all permitted under the regulations.
On April 14th, 2016. See this statement in context.