In a narrow 5-4 decision on August 20, 2015, the Washington Supreme Court reversed a lower court ruling and applied the City of SeaTac’s $15 minimum wage law to all workers at Seattle-Tacoma International Airport. 

The law, which became effective on January 1, 2014, was one of the nation’s first $15 minimum wage propositions. SeaTac voters narrowly approved the wage hike two years ago, which applies to only “hospitality” and “transportation” workers within the city limits.

However, an airline, a restaurant group, and a food company each sued the city, arguing that the minimum wage proposition could not be enforced against workers at SeaTac Airport because the facility is operated by the Port of Seattle. A lower court agreed, and in a December 2013 decision, ruled that the law could not be enforced because of the Port of Seattle’s exclusive jurisdiction over the airport’s “operations” and its workers. The lower court made clear, however, that the $15 minimum wage still applied to workers at nearby hotels and parking lots who worked outside the airport boundaries.

Last week, the Washington Supreme Court overturned this ruling and upheld the law’s reach into SeaTac airport. The court’s ruling states that the law granting the Port of Seattle operational control of the airport was intended to “vest authority for the operation of the airport exclusively with the Port of Seattle, but not to prohibit a local municipality like the city of SeaTac from regulating for the general welfare in a manner unrelated to airport operations.”

The court decided that the airport and its workers are still subject to state minimum wage laws, which are enforced by municipalities, and which “sets the minimum wage in any given location at the most favorable level to the employee whether by federal, state or local law.”

Still unclear from the court’s decision is whether the pay bump will be retroactive to January 1, 2015. The state Supreme Court simply stated that the law “can be enforced” at SeaTac Airport, presumably leaving hospitality and transportation employees the right to enforce the payment of their wages against their employers if their employers do not pay them back to the beginning of the year. If so, airport employees could have a costly cause of action against transportation and hospitality employers, as the ordinance mandates the payment of attorney fees in addition to any back wages award pursued in court.