The crack growth behaviour of low density polyethylene in various organic liquids shows that there is a correlation between the crack speed and the solubility parameter of the environment. The detergent solutions, which are micellar in water, were found to be more effective in cracking the specimens than solutions without micellar structure. The addition of small amounts of solubilizates, such as xylene, to the micellar solution increased the crack growth rate. Williams' flow model is found to be inadequate to describe the crack growth behaviour. A qualitative model for crack propagation considers that the combination of the sorption properties of the polymer and viscous flow of the swollen material leads to crack growth. © 1987.