O'Neill Service Group

About us

You may have heard our name (O’Neill Service Group/OSG) from a business colleague, client, or friend.  We have gained a reputation of having small firm values yet large firm expertise, talent and resources.  We believe it is partly due to our unique story.

Our StoryOGS Geological Services, Environmental Services Bellevue, WA

In 2008, Dennis O’Neill first established O’Neill Environmental Services (OES) with a goal to provide Environmental and Geological Services to several local general contractors in the Puget Sound Region.   As a young company, the firm experienced exceptional growth despite the country’s most challenging economic times.  Success was the result of our team approach, technical expertise, responsiveness and commitment to client service.  We continue to evolve through innovation, adaptability and establishing a positive and respected reputation in the construction industry.