Silica is one of the most common hazards at construction sites. Workers exposed to airborne respirable silica are at an increased risk of developing lung diseases like silicosis, lung cancer and chronic obstructive pulmonary disease. Meghan Friesen, Occupational Hygienist with the Ontario Health Clinics for Ontario Workers, discusses the hazards and health effects of silica, exposures in the construction industry, and the free online Silica Control Tool.