Five statistical procedures were used to partial the correlation between water-borne asbestos and digestive site cancer for the putative effects of population density. These include: analysis based on a data subset with roughly homogeneous population density; standard residual analysis (partial correlation); conditional probability integral transformation; analysis based upon ranked data and use of the logarithmic transformation. Monparametric regression graphical techniques are applied to examine the nature of shape of the asbestos-cancer dose-response curve. Evidence is presented which suggests that there is considerable difference between analyses involving non-high density tracts and non-San Francisco tracts. Evidence is also presented that the modal-type nonparametric regression curve forks or bifurcates when adjustment is made for population density.