Gov. Tom Corbett said Monday the tests were performed after rainwater samples collected on Friday at the state's nuclear power plants registered very low concentrations of radiation, apparently from the Japanese nuclear plant damaged by an earthquake and tsunami.
Testing over the weekend was performed in six regions of Pennsylvania. Corbett says there's no risk to the public, and state agencies will continue to monitor the situation.
In Massachusetts, officials said Sunday that one rainwater sample registered very low levels of radiation from radioiodine-131, which is short-lived. They said it posed no threat to drinking water or public health.