Lawyers for the Army and the Colorado health department are returning to court after reaching an impasse in negotiations on monitoring chemical weapons stored outside Pueblo.

A conference is scheduled Friday in federal court in Denver.

The two sides announced an agreement in January on the state's lawsuit seeking stepped-up monitoring of the 2,600 tons of mustard agent at the Pueblo Chemical Depot, and they were discussing how to implement the agreement.

They told a federal magistrate this month they had reached an impasse on two issues: whether the munitions should be considered waste, and the level of protection workers should have against chemicals other than mustard.

They say they agreed on the other issues.

The Army is building a plant to destroy the mustard.

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