The absence ol' citiLcn mobilization following the announcement oP high levels of dioxin in a New England rivcr, and subsequent Superfund listing, is cxplained in light of previous research that stresses the conflict and controversy that surround community contamination. Interviews with area residents and government officials, observations of public meetings, and content analyses of newspapcr articles, EPA press releases, and other official documents provide three explanations for the absence of citizen mobilization: (1) shared knowledge of the community's industrial history meant the river's contamination did not disrupt taken-for-granted assumptions about the community, (2) the "discovery" of the contamination by a government agency and its subsequent impression management served to defuse the public outrage that would otherwise lead to controversy and confrontation, and (3) elected officials, who were able to get resources to the agencies that could handle the problem, supported the decisions of the agencies rather than criticiring them or accusing them of negligence.