SLU development cleaning up area's contaminated sites



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Posted on December 19, 2013 at 7:15 PM

Updated Monday, Dec 23 at 3:54 PM

It can be dangerous to drive, walk or ride a bike through South Lake Union (SLU) these days.

The area has become one of Seattle’s fastest growing development zones. It’s an educational, tech and urban housing center that is growing so fast, it sometimes feels like you can’t get in or out.

But each one of those rapidly rising towers and complexes actually represents an environmental achievement. Developers are required to clean up any contaminates in the soil before they proceed and there is plenty to clean up. State Department of Ecology investigators listed 88 contaminated sites in SLU.    

South Lake Union was an industrial and warehouse center for most of the last century. It was filled with shops and laundries and garages that serviced downtown Seattle. Most of those old businesses are long gone, but they left toxic plumes of pollutants that are dangerous for Lake Union and workers who may come in contact with them during excavation.

Developers are using several techniques to clean up the sites and every method they choose is expensive. For one technique,  technicians are heating the ground, not digging it up. While the ground is not hot to the touch, underneath it's boiling. Electrodes are inserted deep into the ground, then powered up to produce incredible heat. Any contamination in the soil that's volatile is vaporized. The vapor is then sucked out of the ground with giant filters.

State Ecology officials say there is no way the state could afford to clean it up, so they are encouraging developers to work with them to make sure their properties are clean up before they start digging or building.

To date, 41 of the sites have been cleaned up, 35 cleanups are underway and 12 sites are awaiting cleanup. Most of the new buildings also use advanced methods for handling storm water runoff and other environmental problems usually associated with development.

All that development will have some negative effects but, at least as far as the soil is concerned, South Lake Union is looking a little cleaner on every corner.

SLU Cleanup sites