Complex sentence: The firm was engaged by attorneys representing many of the landholders in Alaska to evaluate the impacts of the Exxon Valdez oil spill, and its research resulted in development of many of the more advanced methods widely used in the appraisal profession today.
Split into simpler sentences: The firm was engaged by attorneys representing many of the landholders in Alaska to evaluate the impacts of the Exxon Valdez oil spill. Their research on this project resulted in development of many of the more advanced methods widely used in the appraisal profession today.