Versions of See prior versions of a law on LawServer 2023 Washington Code 28B.20.450 – Occupational and environmental research facility — Construction and maintenance authorized — Purpose 2022 Washington Code 28B.20.450 – Occupational and environmental research facility–Construction and maintenance authorized–Purpose 2020 Washington Code 28B.20.450 – Occupational and environmental research facility — Construction and maintenance authorized — Purpose 2019 Washington Code 28B.20.450 – Occupational and environmental research facility — Construction and maintenance authorized — Purpose 2018 Washington Code 28B.20.450 – Occupational and environmental research facility — Construction and maintenance authorized — Purpose 2016 Washington Code 28B.20.450 – Occupational and environmental research facility–Construction and maintenance authorized–Purpose 2015 Washington Code 28B.20.450 – Occupational and environmental research facility–Construction and maintenance authorized–Purpose 2014 Washington Code 28B.20.450 – Occupational and environmental research facility — Construction and maintenance authorized — Purpose 2013 Washington Code 28B.20.450 – Occupational and environmental research facility — Construction and maintenance authorized — Purpose 2009 Washington Code 28B.20.450 – Occupational and environmental research facility — Construction and maintenance authorized — Purpose