In the present study the effect of metal poisoning was studied in a natural rubber (NR)-based tire-tread compound. The experimental compound contained 1000 ppm copper metal as an additional ingredient. A detailed study was carried out and the results of the experimental compound were compared against a control compound having no metal ion. The effect of metal poisoning was not significant in the case of the green experimental compound, even after prolonged storage of 150 days. However, the cured experimental compound deteriorated substantially after ageing in aerobic-, anaerobic-, oil-, and out-door-ageing conditions. The ozone resistance property of the experimental compound also proved to be inferior. The degradation kinetic of metal poisoning was found to be a first-order reaction and the service life (as expressed by the half-life period) was drastically reduced for the poisoned compound. (c) 2005 Wiley Periodicals, Inc.