In order to investigate the effect of concurrent phoning and auditory environmental monitoring, the performance of visually impaired people was observed on a dual task that consisted of two simulation tasks. Subjects wore either a bone conducting headset, or closed or open (air conduction) earphones. Reaction times and the correctness of responses on both tasks were studied. Contrary to our expectations, correct responding on the simulated environmental monitoring task was severely delayed (irrespective of earphone). In contrast, responding on the cellphone simulation task was as fast under dual as under single task conditions. This research suggests that regardless of the type of earphone used, blind or visually impaired people should be warned against use of a cellphone when they have to simultaneously monitor the environment and respond quickly to it. By showing that concurrency of two auditory tasks may impede performance, this research extends on previous research that showed interference of conversing on visual tasks. (Contains 4 figures and 2 notes.)