Washington ports may have to spend hundreds of millions of dollars if the Port of Tacoma and a cargo-handling company lose a lawsuit alleging that letting rain that falls on a dock drain into Puget Sound violates the Clean Water Act, according to the Washington Public Ports Association.

The suit, filed by Puget Soundkeeper Alliance, claims the port and SSA Terminals should collect and test the rainwater that hits a 12.6-acre dock for pollutants, particularly copper and zinc. The port says wharves must shed rain quickly for the safety of workers.

Representing 75 port districts, the association has filed an amicus brief with the U.S. District Court for Western Washington to support the port’s position. To collect rainwater running off docks, ports statewide would have to spend $400 million, the association estimates.

Docks typically have hundreds of drains and connecting each hole to a pipe would be a tough engineering feat and could lead to water backing up, the port association’s executive director, Eric Johnson, said in a court filing. “These decks, for obvious safety reasons, cannot accommodate pooling or running water,” he declared.

Though not parties to the lawsuit, the port association and the like-minded Washington Maritime Federation are seeking to have their concerns considered. Soundkeeper calls their brief “unhelpful” and has asked the presiding judge, Benjamin Settle, to disregard it. The judge has yet to rule on the issue.

Through Washington ports, $15 billion worth of food and other agricultural products were exported in 2017, according to the state Department of Agriculture. Some $7 billion of those farm goods originated in Washington.

A frequent litigant in Clean Water Act citizen suits, Soundkeeper has filed a similar lawsuit against the Port of Seattle and one of its tenants, Total Terminals International. In their brief, the port association and maritime federation claim Soundkeeper may be planning more suits.

“Soundkeeper has sent other ports threatening messages through public records requests concerning discharges from wharfs and docks, suggesting that Soundkeeper is likely to file similar suits throughout the state,” the brief states.

The brief did not identify the other ports or detail how the port association calculated how much collecting rain would cost ports. Efforts to get more details from the association Monday were unsuccessful.

Soundkeeper Executive Director Chris Wilke said his organization has no immediate plans to file similar suits.  “If they feel public record requests are threats, they should re-examine their commitment to public transparency,” he said.

Installing stormwater collection systems on docks would create jobs, as well as protect water, Wilke said. “That is not money flushed down the drain,” he said.

Soundkeeper originally filed the lawsuit in 2017 against APM Terminals, a Netherlands container company. APM gave up its lease later that year, and SSA Marine, a global company with headquarters in Seattle, leased the terminal. Soundkeeper amended the lawsuit and named the Port of Tacoma and SSA as defendants.

In a motion pending before the judge, the port has moved to dismiss the suit. The port argues the Clean Water Act would only apply if industrial activities such as repairing equipment or cleaning vehicles took place on the dock.

The port says 210-ton cranes that load and unload containers have no wheels, engines or fuel, and run on electric rails. “The purpose of the deck drains is to allow for the rapid discharge of rainwater from the wharf in order to protect worker safety, particularly in regard to the electrocution hazard posed by the crane rails,” according to the port’s motion.

Soundkeeper maintains the Clean Water Act does apply and notes cranes are oiled and lubricated and trucks “zig-zag across the wharf.” The organization hired an expert in managing stormwater who said he inspected the dock and saw grease spots.