The Railroad Commission of Texas, the state’s regulator of the oil and gas industry, spent millions of dollars plugging hundreds of wells in 2016, but it still fell short of its goal to plug nearly 900 wells, according to the agency’s Oilfield Cleanup Program Annual report.

The report was discussed during Tuesday’s commission meeting, the last meeting for this year. The agency is tasked with plugging thousands of wells abandoned by oil and gas operators, and uses a mix of federal grants and industry fees to pay for it. The state’s backlog of so-called orphan wells is estimated to be more than 9,000. Inactive wells that go unplugged are considered a health and safety hazard, and state regulations require that operators plug wells. Often, when operators can’t pay to plug a well, the state assumes the cost.

— Houston Chronicle