A model of the North Atlantic Ocean is used to simulate the spreading of CFC-12 from the Labrador Sea deep convection site. The standard version of the model fails to capture the local maximum in CFC-12 concentration that is observed along the continental slope of the western boundary. Hydrographic data are used to apply a simple correction to the model's horizontal momentum equations. The corrected model is much more successful at capturing the nearslope maximum in CFC-12 concentration than the uncorrected model and also exhibits a 50% increase of the deep southward export of CFC-12 at 24¿N. The difference between the two model runs is shown to be a consequence of the different paths taken by the Deep Western Boundary Current in the two model versions.