A Missouri environmental group sued regulators Thursday, charging the government with failing to protect 80 percent of Missouri's waterways from pollution.

The Missouri Coalition for the Environment filed a lawsuit in federal court accusing the U.S. Environmental Protection Agency of failing to apply standards to roughly 150,000 miles of Missouri streams and rivers.

"The condition of our water today is a result of the fact that we've ignored water quality standards on 80 percent of the waterways in Missouri," said Kathleen Logan Smith, the group's executive director. "We can't afford to continue down this path."

Under the 1972 Clean Water Act, states are required to give permits for the discharge of pollution. In Missouri, state regulators give discharge permits in larger, classified waters — the Mississippi and Missouri rivers, for example — and unclassified waters, such as Ballwin's Kiefer Creek. Permits issued for unclassified waters, however, don't have specific discharge limits and are difficult to enforce or patrol.

"They're not enforced as a routine matter," Logan Smith said.

As a consequence, the larger, classified bodies of water in the state are receiving water from tributaries where pollution standards aren't being adequately policed, Logan Smith said. The majority of discharges in the state go into these unclassified waters, later ending up downstream.

"If you're dumping into streams, then it's not going to be good downstream," Logan Smith said. "People tell me stories about how they used to swim here, and, quite frankly, you can't do that anymore."