This study analyzes the relationship between internal and external factors that influence environmental behaviour in traditional service micro-enterprises, focusing on Chicago motor vehicle repair (MVR) firms five years after the Clean Break amnesty program and subsequent inspections of MVR firms. The survey explored the influence of firm and manager characteristics, government intervention, and market and social pressures and opportunities on environmental awareness and action. Environmental action was significantly higher in older firms (more experienced owners) and in auto-refinishing firms practicing spray painting. While awareness levels were mixed for dealerships and franchises (contracted to larger organizations), environmental action was good for six out of the seven firms, which may reflect expectations for higher professional rather than environmental standards. However, environmental awareness and behaviour levels were mixed for trade association members. Owners obtain most environmental information from suppliers and government agencies, but confuse government responsibilities and attribute greater authority to non-environmental agencies. Finally, micro-enterprises avoid voluntary environmental compliance programs and prefer targeted enforcement and insurance requirements that promote a level playing field.