This paper provides an extension of the work of Balakrishnan and Ling by introducing a competing risks model into a one-shot device testing analysis under an ALT setting. An expectation maximization (EM) algorithm is then developed for the estimation of model parameters. An extensive Monte Carlo simulation study is carried out to assess the performance of the proposed method. The performance of the EM algorithm and the Fisher scoring method are also compared. Finally, the proposed EM algorithm is applied to a modified Class-B insulation data for illustrating the results developed here.