WASHINGTON (Reuters) - Most U.S. states have cut funding and staffing at their environmental agencies over the past decade, according to a study by a green advocacy group, raising questions about the Trump administration’s policy to shift more enforcement of federal environmental laws to states.

FILE PHOTO: Pump jacks operate in front of a drilling rig in an oil field in Midland, Texas U.S. August 22, 2018. PREUTERS/Nick Oxford

The report by the Environmental Integrity Project released on Thursday showed some 30 states have reduced funding for pollution control programs, 16 of them by more than 20%. Forty states, meanwhile, have cut staffing at environmental agencies, half of them by at least 10%, the report showed.

The study marks the latest in a three-year campaign by environmental groups, conservationists, and progressive lawmakers to fight President Donald Trump’s efforts to roll back federal regulations and oversight to ease the way for business.

Over the last decade, the U.S. Environmental Protection Agency’s budget and work force have both decreased by 16%, and the Trump administration has proposed slashing the agency’s budget further while shifting more of its work to states.

Trump has said cuts to EPA funding, as well as rollbacks to certain environmental regulations, can be made without harming U.S. air and water quality – something his critics says is misguided at a time of soaring oil and gas development and increased urgency over climate change.

“Neither EPA nor states have the funding they need to meet their responsibilities under the Clean Air Act, Clean Water Act and other laws that protect the public’s health and our environment from dangerous pollution,” said Eric Schaeffer, executive director of the EIP.

EPA spokeswoman Molly Block did not comment on the specifics of the EIP report, but said: “The EPA is fully committed to fulfilling our mission of protecting human health and the environment and working closely with our state, local, and tribal partners.”

EIP said its research was based on annual expenditures and staffing level data published by state agencies covering the years 2008 to 2018.

It said two of the states that have seen the biggest cuts in spending for environmental programs - Texas and Pennsylvania - have also seen the most growth in oil and gas drilling over the last decade.

Six of the 10 states that have seen the sharpest environmental budget cuts - including Louisiana, North Carolina and New York - are coastal states that have been hit by increased coastal flooding, it added.