The rules restrict the level of phosphorous in Oklahoma's six designated scenic rivers to 0.037 parts per million. Arkansas is affected because the Illinois River flows from Arkansas to Oklahoma. Arkansas Gov. Mike Huckabee has opposed the standards as being unrealistic and impossible to meet without widescale business disruptions in his state.

Oklahoma officials said Arkansas must comply with the new standards under a 1992 U.S. Supreme Court opinion that said upstream states are subject to downstream water quality regulations.

Keating said the rules are needed because voluntary restrictions had not worked. The voluntary 40 percent phosphorus reduction agreed upon by both states has resulted in no improvement to the Illinois River.

Doug Szenher, spokesman for the Arkansas Department of Environment Quality, said officials from his office plan to meet with Oklahoma environmental officials. Gov. Huckabee said Arkansas would work diligently to improve water quality standards throughout the state.