SAN FRANCISCO (AP) — California regulators on Thursday proposed an Oct. 15 deadline for starting to close more of the 2,000-plus oil-industry wells that funnel waste and other fluids into federally protected underground water reserves.

State lawmakers, the U.S. Environmental Protection Agency and environmental organizations stepped up pressure this year on state oil and gas regulators to stop injection of the wastewater and other fluid into current and potential sources of drinking water.

A state audit ordered by the EPA determined last year that state oil and gas regulators had Improperly granted more than 2,500 permits authorizing oil companies to inject potentially contaminating fluids into water basins that are classified as clean enough to qualify for federal protection under the U.S. Safe Drinking Water Act.

An Associated Press analysis found the state had granted hundreds of the permits since 2011, despite increasing warnings from the EPA.

State officials told a state legislative hearing last month that water aquifers contaminated by oil industry injections are all but impossible to clean.

“We understand public concern about their water,” senior state oil and gas regulator Steve Bohlen said Thursday in a statement outlining the Department of Conservation’s planned steps for dealing with the injections.

Since last summer, the state has closed 23 of the injection wells that were deemed most threatening to water wells.

Bohlen said Thursday that decisions on closing any additional high-risk injection wells immediately would be made in coming weeks.

After that, the state plans an Oct. 15 deadline for stopping oil-industry injection into top-quality water aquifers, officials said.

More deadlines will follow through Feb. 15, 2017, when all injection into aquifers under federal protection must cease, state officials said.

Environmental groups said all the improperly permitted oilfield injection into protected water aquifers should stop now.

“During the worst drought in California history, state officials think the emergency is that the oil industry will be inconvenienced if it can’t continue polluting our underground water,” said Patrick Sullivan of the Center for Biological Diversity.

Regulators’ plan for the improperly permitted oilfield injection now goes up for a brief period of state and public review.