Laborers Local 483 (LIUNA)
LIUNA  is a union that builds and maintains the infrastructure of Portland. This ranges from roads to waste water treatment to public facilities and more. Most of the members are in construction-based industry.
The union was founded, when workers overcame adverse circumstances that included "... hostility, threats and violence..." to form in solidarity of voice to be heard.
LIUNA is established in the US and Canada, with over 12 million members, and is responsible for 5% of those countries gross national product.
The union most recently announced that it backs the Occupy Wall Street | Occupy Together Movement . To that end, they issued a statement of unity with the Occupy Portland civil action.