Police are investigating the fire in Ridgefield in which 25 gallons of gasoline was poured on the field Saturday.
First Selectman Rudy Marconi told Hearst Connecticut Media that 75 to 100 people watched as it happened, with some recording video on their cellphones. The town's high school baseball team had been planning to host Amity on the field.
Workers from the state Department of Energy and Environmental Protection responded. A hazardous waste removal crew began digging up the contaminated soil Sunday, and Marconi says the spill team will move it off site this week.
No one has been charged.