Great Kills Park was created by the New York City Department of Parks between 1934 and 1951. Approximately half of the park resides on waste material used by New York City to fill the wetlands when it established the park. The park was transferred to the National Park Service (NPS) in 1972 as part of Gateway National Recreation Area.

Radiological contamination was first discovered in Great Kills Park (GKP) in 2005 during an aerial survey conducted by New York City and the U.S. Department of Energy to develop a baseline radiological map of the city. From 2005-2007, additional areas of radiological contamination, mainly from radium 226, were found within Great Kills Park.

Radiation is energy given off by atoms and is present in nature all around us. Everyone is exposed to low levels of radiation every day from naturally occurring radioactive elements, from cosmic (sun) rays, and man-made exposures like medical x-rays. Exposure from cosmic rays increases with altitude above sea level. On average, radiation from natural sources is responsible for about eighty percent of the radiation U.S. residents receive annually.

Exposure to radiation can cause cancer. Radium has been responsible for causing cancer in workers who used it to paint watch dial faces. They ingested radium when they put their brush tips into their mouth to make a fine point to apply the radium paint. Additionally, radon gas is a by-product of radium 226 decay. Radon is suspected to cause lung cancer in uranium miners, and can become concentrated in homes in certain areas of the country. While these conditions do not exist at the Park, NPS must clean up in accordance with CERCLA and to fulfill our mission, which is to preserve and protect for future generations.

For comparison purposes, radioactivity is present in our bodies at about 29 mrem per year.Mrem stands for millirem- or 1/1,000 of a rem, which is the unit that measures what effect radiation has on tissue. Getting a chest x-ray gives us 10 mrem per X-ray. A dental x-ray is 1 mrem per x-ray.

The National Park Service has taken measures to ensure the public is safe while the investigation and clean-up is ongoing. The greatest health risk at the site is from direct contact with the source of radioactive contamination. The areas that are open to visitation are considered safe. In the closed areas exposure, and ultimately risk, depends on the amount of time and how close you are to the actual source of the radiation. The National Park Service has installed fencing to restrict access to the contamination to prevent such contact and signage to inform visitors of the closed areas. The established boundaries put visitor safety, our highest priority, first.

Contractors are currently working at GKP to complete a radiological survey and to remove or continue to restrict access to areas with elevated radioactivity. By the summer of 2014, the NPS will have installed more than 18,000 feet of perimeter fence, cut back vegetation and performed a gamma survey over 265 acres, and excavated areas with the highest levels of radioactivity.

Through the course of implementing these response actions, NPS has learned that the radiological contamination is more widespread within the fill material than previously thought and is not limited to buried discrete hotspots. Although the current actions will protect public health and the environment for the short term, NPS has determined it is appropriate to initiate further investigations to characterize the extent of the remaining contamination. The investigation will include screening for potential non-radiological contaminants. Once the investigation is complete, NPS will conduct a feasibility study to evaluate the effectiveness of various alternatives to address any remaining risks and comply with all applicable standards. The National Park Service is the lead agency pursuing the clean up of Great Kills Park as prescribed under the Comprehensive Environmental Response, Compensation, and Liability Act. This federal law is commonly called the “Superfund” law.

Go to the Community Involvement page to sign up for our email list to receive updates. You can learn more about the project and download copies of key documents from the Environmental Investigations page. You can also email

Information about radiation and radium in general can be found from the following sources:

  • Agency for Toxic Substances and Disease Registry (ATDSR) –
  • The National Institutes for Health:
  • Argonne National Laboratory:
  • Health Physics Society: