include restructuring charges, such as asset impairments, exit costs and severance costs (including any related impacts to our benefit plans, including settlements and curtailments) and associated implementation costs, such as accelerated depreciation charges, primarily associated with plant network optimization efforts, and expenses associated with system and process standardization and the expansion of shared services (see Notes to Consolidated Financial Statements— Note 4. Adapting to Scale Productivity Initiative).

We incurred the following costs in connection with our AtS productivity initiative:

restructuring of our U.S. marketing and worldwide research and development operations, and the implementation costs primarily relate to system and process standardization, as well as the expansion of shared services.

The components of restructuring charges associated with AtS follow:

Through December 31, 2006, Employee termination costs represent the approved reduction of the workforce by 8,274 employees, mainly in manufacturing, sales and research. We notified affected individuals and 5,732 employees were terminated as of December 31, 2006. Employee termination costs are recorded as incurred and include accrued severance benefits, pension and postretirement benefits. Asset impairments primarily include charges to write down property, plant and equipment. Other primarily includes costs to exit certain activities.

Acquisition-Related Costs

We incurred the following acquisition-related costs, primarily in connection with our acquisition of Pharmacia on April 16, 2003:

In connection with the acquisition of Pharmacia, Pfizer management approved plans to restructure and integrate the operations of both legacy Pfizer and legacy Pharmacia to combine operations, eliminate duplicative facilities and reduce costs. As of December 31, 2005, the restructuring of our operations as a result of our acquisition of Pharmacia was substantially complete. Restructuring charges included severance, costs of vacating duplicative facilities, contract termination and other exit costs. Total acquisition-related expenditures (income statement and balance sheet) incurred during 2002 through 2006 to achieve these synergies were $5.2 billion, on a pre-tax basis.

Cost synergies from the Pharmacia acquisition were $4.2 billion in 2005 and $3.6 billion in 2004. Synergies come from a broad range of sources, including a streamlined organization, reduced operating expenses, and procurement savings.

Substantially all of our restructuring charges in connection with the Pharmacia acquisition were completed through December 31, 2005 and we recorded, in total, $1.2 billion by that date into the income statement. These restructuring charges were associated with exiting certain activities of legacy Pfizer and legacy Pharmacia (from April 16, 2004), including severance, costs of vacating duplicative facilities, contract termination and other exit costs. As of December 31, 2006, liabilities for these restructuring charges incurred but not paid totaled $77 million and are included in Other current liabilities.

The majority of the restructuring charges related to employee