The field is across the street from BP Oil Inc.'s Mantua Avenue tank farm.
Mayor James Sabetta said that the petroleum product does not appear to present a problem to children using the playing fields because of a layer of clay in the soil. He said the contaminants are at least 22 feet beneath the surface.
BP has said it would like to install two more testing wells, in addition to the six the town already has.
Borough engineer Terry Vogt said he suspected that the leak is larger than what BP indicated in a report presented to the borough last month. He said the petroleum products have turned up in a monitoring well on Beacon Avenue.
Vogt said he believes that BP needs to install another monitoring well farther south on Beacon Avenue to determine where the contamination ends. He said as many as two additional monitoring wells may need to be installed, in addition to the two BP wants to install.
When the problem was discovered last year, it was thought to have affected about 24 properties in less than a two-block area.
BP, in the midst of a cleanup of its Mantua Avenue property ordered by the Department of Environmental Protection, has been monitoring the extent of neighborhood contamination since last year, when a nearby resident detected the odor of gasoline in her basement.
BP has since purchased that resident's home.