Previous studies of the diffusion of gases and organic vapors at low concentrations in glassy polymers have established the applicability of Fickian kinetics, the correlation of diffusion coefficients with the dimensions of the diffusing molecules, and the impracticality of experimentally measuring the diffusivities of molecules larger than C-6 hydrocarbons. The diffusivities of the suspected endocrine disrupters, p-nonyl phenol, bisphenol-A, and tetrachlorodioxin, have been estimated by extrapolation of the established correlations of diffusivity with mean molecular diameter. Estimated diffusivities of these substances in glassy polystyrene, poly(vinyl chloride), and poly(methyl methacrylate) at 30 degrees C range from 10(-17) to 10(-26) cm(2)/sec. Calculations of desorption rates, based on Fick’s law, show that it would take from several hundred to millions of years for even 1% of the initial content of an endocrine disrupter to migrate from a glassy polymer sheet 1 mm thick. It therefore seems that migration from rigid polymer products should not be considered a significant source of endocrine disrupters in the environment.