San Carlos Indian Irrigation Project Divestiture Act of 1990

San Carlos Indian Irrigation Project Divestiture Act of 1990 - Directs the Secretary of the Interior to transfer U.S. interests in the electrical system of the San Carlos Irrigation Project (SCIP) in Arizona to: (1) the Gila River Indian Community (GRIC) and the San Carlos Apache Tribe (SCAT) for the portions of the system on their reservations; and (2) the San Carlos Irrigation and Drainage District (SCIDD) for remaining portions. Directs the Secretary to negotiate an agreement with GRIC, SCAT, and SCIDD for the transfer of project assets and to distribute those assets in a manner that reflects the proportionate number of miles of distribution line to be transferred to GRIC, SCAT, and SCIDD. Requires the Secretary to retain ownership of the electric generating and maintenance facilities located in the power house and switchyard at Coolidge Dam.

Directs the Secretary to establish the Environmental Protection Account, to be administered by SCIP in consultation with GRIC and SCAT to supplement existing sources of funding for disposal of hazardous waste materials associated with the SCIP electrical system.

Directs the Secretary to study repairing, replacing, or upgrading the electric power generators in the powerhouse at Coolidge Dam. Authorizes appropriations for such study.

Directs the Secretary of Energy, upon the request of the Secretary of the Interior, to enter into agreements to reallocate SCIP's allocation of Federal preference power capacity and energy. Directs the Secretary of Energy to treat GRIC, SCIDD, and SCAT as successors in interest to SCIP in reallocating SCIP's allocation of capacity and energy from the Parker Davis Project and the Colorado River Storage Project, including capacity and energy available pursuant to any agreement to provide preference power to SCIP prior to July 1, 1991. Assigns SCIP allocations of winter and summer capacity and energy to GRIC, SCIDD, and SCAT. Requires SCIP to assign its allocation of the capacity and energy from the Boulder Canyon Project accordingly.

Requires the Secretary of the Interior to provide for the allocation of the unobligated balances of SCIP funds to GRIC and SCAT for specified uses. Requires SCIP debt obligations owed by GRIC and SCIDD to the United States to be deposited in the Environmental Protection Account.

Entitles any Federal employee at SCIP whose position is terminated by this Act to elect to continue receiving workers' compensation, retirement, and health and life insurance benefits for his or her period of employment with the tribal authority provided such authority deposits employee deductions and agency contributions in the appropriate funds. Directs the Secretary to establish and maintain a Departmental Priority Placement Program for SCIP employees who are involuntarily separated as a result of the divestiture of the SCIP electrical system.