The state Department of Environmental Protection has announced a yearlong study of radiation levels in equipment and wastes associated with oil and gas development it says will be the "most extensive and comprehensive" ever conducted.

The regulatory agency announced the study Thursday and said it will test radiation levels at dozens of well pads, wastewater treatment plants and waste disposal facilities statewide.

Oil and gas-bearing rock formations like the Marcellus Shale contain naturally occurring radiation that is brought to the surface in wastewater and rock waste. It can concentrate on pipes or equipment or in wastewater sludges. Some fluid samples from shale drilling indicate "significant concentrations" of radium 226, a naturally occurring radioactive metal, according to the study proposal by Perma-Fix Environmental Services of Pittsburgh.

The department said data it has reviewed to date show "very low levels of natural radioactivity" in oil and gas wastes and "do not indicate the public or workers face any health risk from exposure to radiation from these materials."

Less than half a percent of the Marcellus Shale rock waste taken to state landfills in 2012 triggered radiation monitors, DEP said, and tests in 2011 of rivers and drinking water intakes downstream of facilities that once treated and discharged Marcellus Shale wastewater found that any detected radiation was below safe drinking water standards.

The study "is aimed at ensuring that public health and the environment continue to be protected," the agency said.

DEP spokesman Kevin Sunday said the study is "very forward-looking" with a goal of adapting to changing technology. For example, the now common practice of recycling or reusing wastewater from one well to extract gas from another helps keep the fluid out of streams, but it may increase radioactivity in sludges.

"We want to make sure those continue to be disposed of safely," he said.

The study will evaluate radiation across the oil and gas production process, including drilling, storage, transportation, treatment and disposal. It will look at radon levels in natural gas, radiation in the leachate collected at 54 landfills in the state, and potential exposure pathways for workers and the public. It will also evaluate the potential need to set radioactivity limits in wastewater permits.

The DEP said it will seek a peer review of its study plan and begin sampling "in the coming weeks." It will also post the peer-reviewed plan online, provide progress reports to its advisory councils and make the final report available to the public.

Contact the writer: llegere@timesshamrock.com