Summary: Revises Tariff WN-6, Schedule 303, Washington Environmental Cost Recovery Mechanism, for remediation expenses associated with natural gas services incurred between January 1, 2023, and December 31, 2023, increasing revenues by $684,585, or 0.56 percent. A residential customer with average monthly usage of 57 therms would see a bill increase of $0.44 per month, or approximately 0.5 percent.