Crews installed three groundwater testing walls at the Brentwood park where toxic material was found dumped earlier this year.

Roberto Clemente Park has been closed to the public ever since 50,000 tons of toxic materials were found at the park last spring.

The town of Islip says it plans to remove all of the illegally placed material and take ground samples to make sure nothing is contaminated. Drinking water will also be monitored for decades as a precaution.

Town of Islip Supervisor Tom Croci says the town cannot remove any of the debris until the state's Department of Environmental Conservation approves. The DEC told News 12 Long Island that it is committed to cleaning up the park and will work with local leaders to ensure public health is protected.