(KRON) -- Chevron will lay off about 600 employees at its former headquarters in San Ramon, KRON4.com has confirmed. The news was first reported in the San Francisco Chronicle. Chevron announced the layoffs as part of Chevron's efforts to streamline organizational structure, improve operational efficiency and enhance long-term competitiveness. "Chevron is taking action to simplify our organizational structure, execute faster and more effectively, and position the company for stronger long-term competitiveness," said Chevron Manager of State Government Affairs Henry Perea, in a letter to officials. "This means we will have fewer positions and unfortunately, fewer people." Earlier this year, Chevron announced plans to cut 15% to 20% of its global workforce as part of a plan to reduce overall structural costs by $2 to $3 billion. Chevron, the second-largest oil company in the U.S., was formerly headquartered at Bishop Ranch in San Ramon. ‘Really Stupid Park’: SF commuters use Great Highway park-naming contest to vent While the company still maintains a significant presence there, it relocated its HQ to Houston last year. The most recently announced layoffs are due to begin on June 1. Chevron says that the job cuts are permanent and that it expects further layoffs. All employees impacted by the latest round of layoffs will receive at least 60 days' notice of their final day of employment, the company said. ...read more read less