Philadelphia physicians were sharply divided over the cause of this terrifying disease. One group of doctors, headed by Benjamin Rush, laid the blame for the epidemic on local causes. Most notable among these causes were the harsh fumes arising from stagnant waters in the marshes surrounding Philadelphia. Other sources of bad air came from decaying vegetable matter and poor public sanitation. Opposing Rush's group was the College of Physicians, who placed the blame for this epidemic on foreign origins, particularly the possibility of infection brought in by ships. A heated debate between these rival factions ensued, with much press coverage. This debate only served to heighten public fears and lessen their confidence in the medical community.