A semi-truck rollover crash closed all lanes to the new northbound lanes of the SR 509 expressway near Normandy Park on Wednesday morning, Sept. 10, 2025, according to the Washington State Department of Transportation (WSDOT).
The crash – on the right shoulder of the entry lanes to northbound SR 509 at milepost 24 near Des Moines Memorial Way S. – prompted a hazardous materials response, and drivers were advised to avoid the area until further notice.
WSDOT first shared info about the crash on social media at 9:10 a.m.
Officials did not immediately release details about injuries or when the roadway might reopen.
Crews are on scene to contain the spill and clear the wreckage.
WSDOT advised drivers to plan alternate routes while the closure was in effect.
Here is what it looks like. pic.twitter.com/WaMVeivPTF
— Trooper Rick Johnson (@wspd2pio) September 10, 2025
UPDATE 2: One right lane of NB SR 509 at Des Moines Way S and the on-ramp from S 188th are blocked due to a collision. We are seeing heavy backups in the area at this time.
— WSDOT Traffic (@wsdot_traffic) September 10, 2025
Continue to expect delays especially around the airport @flySEA @SeaTacWA https://t.co/UNyUqv17D9 pic.twitter.com/rkO5bfVPGu
South 188th St in SeaTac is closed to SR 509.https://t.co/JAlH1g2lsz
— KOMO News (@komonews) September 10, 2025
Hazmat crews respond after semi rollover closes lanes on SR 509 by SeaTac https://t.co/WaLl8rSxC6
— KIRO 7 (@KIRO7Seattle) September 10, 2025
