DescriptionSome environmentally disastrous events lead to significant institutional change while others do not. Consider that the volume of oil spilt at Guadalupe Dunes, California was twice that of the Exxon Valdez accident. Few have heard of the former while the latter has led to significant legislation to control oil pollution. Organizational institutionalists are ambivalent about why events lead to change or even whether they do. Some theorists argue that shocking events break the status quo but what constitutes shocking is unclear. Others argue that events do not by themselves cause change. Instead, individuals or groups who seek change look for events merely as a tool to publicize a problem and recruit support. The central goal of this dissertation therefore is to understand why and how events that arise from industrial accidents that harm the environment lead to significant institutional change. This study is focused on the claims that key actors make in establishing shared meanings that compel the new institution. By devising a comparative case study of four environmental accidents, I have developed a theory to explain why and how events lead to significant institutional change. I find that institutional change occurs when a few people perceive that an industrial accident has disrupted their lives and make claims to problematize the accident as causing an undesirable condition that must be alleviated. These people, labeled problem providers, then engage others, labeled solution providers, to create new meaning or symbolize the event. Such meanings further persuade others to create new institutions to effectively enforce a new order.