The United States Forest Service commenced air tanker loading operations in 1957, and in 1959 California Division of Forestry (now Cal Fire) began their operation at Ryan field. Both agencies maintained separate parking, loading and mixing areas but the initial stages of a joint base operation had begun. In 1969, the United States Forest Service (USFS) and the California Division of Forestry (CDF) truly merged into a joint agency air attack base sharing the base operation, responsibilities and facilities. The joint base concept successfully continued operation until 1998 when the USFS moved their air tanker base operations to the larger and recently vacated Norton Air Force Base.