A physical model of the growth of chemically related failures in electronic components is developed. This model is used to demonstrate that time to failure is as much a function of the component geometry as it is of the activation energy of the reaction. Further interpretation suggests that for any specified failure mechanism the acceleration achieved in a high temperature stress environment will appear to be a variable. Finally, using a simulation technique, a statistical distribution of the times to fail can be generated which resembles very closely the classical exponential failure curve. Copyright © 1986 John Wiley & Sons, Ltd.