ANCHORAGE -

The state of Alaska is agreeing to share the preliminary costs to explore a water-system expansion in North Pole, where a refinery spill decades ago continues to contaminate groundwater.

The agreement covers the expense of developing the design, cost estimate and construction schedule for a water-main extension. It would serve 550 properties with water contaminated by sulfolane, an industrial chemical that was detected in groundwater in 2009.

The Fairbanks Daily News-Miner reports (http://bit.ly/1oRRkb7 ) that the agreement does not include a commitment to follow up with construction work, however.

The deal was announced Friday by the Attorney General Michael Geraghty's office. It requires the state, refinery owner Flint Hills Resources Alaska and the refinery's former owner, Williams Alaska Petroleum, to equally share costs for the preliminary work.