Commercial janitors are an important group of low wage, largely immigrant workers who face significant potential risks at work, and yet have only been minimally studied for occupational injury and illness. Anecdotal reports from a local union representing commercial janitors in the Seattle area suggest pressures on the industry have produced a dramatic increase in workload over the past few years, raising the possibility of increased injury and illness. A cross sectional survey was designed to assess a range of exposures among commercial janitors including both union (n = 275) and non-union (n-75) sectors, and using a group of security guards (n-75) as controls. A novel participatory approach to data collection was developed, utilising workers to recruit subjects and conduct interviews in three languages, using electronic data collection tools linked to an internet-based database. Further, a novel subjective workload scale was adopted, and changes in workload and injury and illness rates over the past three years were assessed. Exposures assessed include general workload, musculoskeletal stressors, chemical use, as well as psychosocial risks such as work stress, safety climate, discriminatory management practices and work-life balance. Outcomes included acute injury, musculoskeletal pain, pulmonary and dermatological symptoms, and sleep disturbance. Initial results indicate a significant increase in workload with 28.5% reporting >7 on a 10 point scale two years ago, up to 35% in the current year. A concomitant increase in injuries was similarly observed. The paper describes the approach to data collection and describes rates of exposure and health and safety outcomes by group. Measures adopted to validate the self-reported conditions are also described.