FIFTH AMENDMENT TO LEASE AGREEMENT

E XHIBIT 10.7.4

FIFTH AMENDMENT TO LEASE AGREEMENT

GRE EMPIRE TOWERS LP,

a Delaware limited partnership

(“LANDLORD”)

AND

KAISER VENTURES, LLC,

a Delaware limited liability company,

p/k/a Kaiser Resources, Inc.

(“TENANT”)

This Fifth Amendment to Lease Agreement (“ Fifth Amendment ”), is made as of March 16, 2009, by and between GRE EMPIRE TOWERS LP, a Delaware limited partnership (“ Landlord ”), and KAISER VENTURES, LLC, a Delaware limited liability company, p/k/a Kaiser Resources, Inc.(“ Tenant ”).

RECITALS

A. Landlord is the Owner of Empire Towers I located at 3633 E. Inland Empire Boulevard, Ontario, California (“ Building ”) and is the successor Landlord to Empire Towers I LLC, a California limited liability company, which was the successor Landlord to Lord Baltimore Capital Corporation previously known as American Trading Real Estate Properties, Inc. under that certain Lease Agreement and Addendum thereto dated June 6, 1994 (“ Original Lease ”), amended by a First Amendment to Lease Agreement dated May 18, 1999 (“ First Amendment ”), a Second Amendment to Lease Agreement dated September 27, 1999 (“ Second Amendment ”), a Third Amendment to Lease Agreement dated February 19, 2002 (“ Third Amendment ”), and a Fourth Amendment to Lease Agreement dated November 13, 2006 (“ Fourth Amendment ”) (collectively referred to as “ Lease Agreement ”), for Suite 480 comprising approximately three thousand one hundred twenty-eight (3,128) gross rentable square feet (“ Premises ”). Tenant is the Tenant under the Lease Agreement.

B. Landlord and Tenant desire to further amend the Lease Agreement on the terms and conditions provided below.

AGREEMENTS

NOW, THEREFORE, in consideration of the mutual covenants contained herein and other good and valuable consideration, the receipt and sufficiency of which is hereby acknowledged, the parties agree as follows:

1. Incorporation of Recitals . All of the recitals set forth above are hereby made an integral part of this Fifth Amendment.

2. Definitions . All capitalized terms not otherwise defined in this Fifth Amendment herein shall have the meaning ascribed to them in the Lease Agreement.

3. Term . Notwithstanding any provision to the contrary contained in the Lease

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Agreement, including, without limitation, Section 3.01 of the Original Lease, Section 3 of the First Amendment, Section 3 of the Third Amendment, and Section 3 of the Fourth Amendment, the term of the Lease Agreement for the Premises is hereby extended for a period of twenty-four (24) months commencing September 1, 2009 and expiring August 31, 2011 (“ Fourth Extended Term ”).

4. Base Rent for the Premises . The monthly Base Rent for the Demised Premises during the Fourth Extended Term shall be as follows:

Notwithstanding anything to the contrary set forth in the Lease Agreement, Base Rent during the period from June 1, 2009, through August 31, 2009, shall be abated in its entirety.

5. Base Taxes . As of September 1, 2009, Base Taxes for the Demised Premises shall mean Taxes for the calendar year 2009.

6. Base Operating Costs . As of September 1, 2009, Base Operating Costs for the Demised Premises shall mean Operating Costs for the calendar year 2009.

7. Tenant Improvements . On or before September 30, 2009, Landlord shall, at Landlord’s sole cost and expense (i) professionally clean the existing carpeting in the Demised Premises, and (ii) paint the Demised Premises utilizing Building Standard paint. Other than the foregoing, Landlord shall have no obligation to prepare the Demised Premises for Tenant’s continued occupancy during the Fourth Extended Term.

8. Option to Extend Term . All options to extend the term of the Lease Agreement, if any, set forth in the Lease Agreement are hereby deleted in their entirety, including, without limitation, Article 43 of the First Amendment and Section 8 of the Fourth Amendment, and are replaced by the Option to Extend the Term described in this Section 8 of this Fifth Amendment. Provided Tenant has cured any default of the Lease Agreement in the prescribed time and manner described in the Lease Agreement at any time from the time Tenant exercises the applicable option as set forth herein until such time as such extended term commences, Tenant shall have two (2) options to extend the term (each an “ Option to