FIRST AMENDMENT TO AMENDED AND RESTATED CREDIT AGREEMENT AND WAIVER

This FIRST AMENDMENT TO AMENDED AND RESTATED CREDIT AGREEMENT AND WAIVER (this “ Amendment ”), dated as of January 14, 2009, among RENTECH ENERGY MIDWEST CORPORATION, a Delaware corporation (“ Borrower ”), RENTECH, INC., a Colorado corporation (“ Holdings ”), the Lenders and the Agents (each as defined below) is entered into in connection with the Credit Agreement referred to in the first recital below.

WHEREAS, Borrower and Holdings are parties to that certain Amended and Restated Credit Agreement, dated as of June 13, 2008 (as amended, amended and restated, supplemented or otherwise modified from time to time, the “ Credit Agreement ”; unless otherwise defined herein, terms defined in the Credit Agreement and used herein shall have the meanings given to them in the Credit Agreement), among Borrower, Holdings, the banks, financial institutions and other entities party to the Credit Agreement as lenders (the “ Lenders ”), Credit Suisse, Cayman Islands Branch, as administrative agent (in such capacity, the “ Administrative Agent ”) and as collateral agent (in such capacity, the “ Collateral Agent ”);

WHEREAS, as of the date hereof, Borrower has requested from Administrative Agent certain amendments and waivers with respect to, inter alia , (i) the mandatory prepayment requirements under Section 2.10(a) of the Credit Agreement and (ii) the Minimum Liquidity Threshold requirement under Section 6.16 of the Credit Agreement.

WHEREAS, the Lenders and Agents have agreed to amend and waive certain provisions under the Credit Agreement to the extent set forth herein and subject to the terms and conditions set forth in this Amendment.

NOW, THEREFORE , in consideration of the premises made hereunder, and for good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the parties hereto, intending to be legally bound, hereby agree as follows:

Section 1.                       Amendment of Section 1.01 of the Credit Agreement .  Section 1.01 of the Credit Agreement is hereby amended by amending and restating the following definitions:

“ Applicable Margin ” shall mean, for any day with respect to any Loan, (a) accruing interest at the Alternate Base Rate, 9.0% per annum, or (b) accruing interest at the Adjusted LIBO Rate, 10.0% per annum.

“ Cash Outlay ” shall have the meaning assigned to such term in Section 2.10(a).

“ Deferral Facility ” shall have the meaning assigned to such term in Section 2.10(f).

“ Deferral Interest Rate ” shall have the meaning assigned to such term in Section 2.10(f).

“ Fee Letter ” shall mean, collectively, each of the Fee Letters dated May 30, 2008, June 13, 2008, and January 14 , 2009 (the “ January 2009 Fee Letter ”) among the Borrower, the Administrative Agent, and an affiliate of the Administrative Agent.

“ First Amendment Effective Date ” shall mean January 14 , 2009, the date on which the First Amendment to Amended and Restated Credit Agreement and Waiver became effective.

Section 2.                       Amendment of Section 2.10 and Section 5.13 of the Credit Agreement .  Section 2.10 and Section 5.13 of the Credit Agreement are hereby amended as follows:

(a)           Section 2.10(a) of the Credit Agreement is hereby amended and restated as follows:

(a)           In the event that Borrower shall make a distribution (including for purposes of payments under the Management Agreement) to any holder of Equity Interests of Borrower (other than any Permitted Distributions/Loans and payments permitted under Sections 6.06(a)(ii) and (iii)) or an intercompany loan to, or other Investment in, Holdings or any other Subsidiary, concurrently with such distribution, intercompany loan or other Investment by Borrower (each, a “ Cash Outlay ”), the Borrower shall deliver, or cause to be delivered, to Lenders, subject to the provisions of Section 2.10(f), an amount to prepay outstanding Loans in accordance with Section 2.10(e) as follows (provided, that such Cash Outlays may only be made in compliance with Section 6.04 and Section 6.06):

(i) beginning and including December 23, 2008, on the first $22,000,000 in aggregate Cash Outlays, an amount equal to 25% of the amount of each such Cash Outlay to prepay outstanding Loans in accordance with Section 2.10(e);

(ii) through and including September 30, 2009, on all Cash Outlays above the $22,000,000 in aggregate Cash Outlays referenced in subsection (i), an amount equal to 75% of the amount of each such Cash Outlay to prepay outstanding Loans in accordance with Section 2.10(e); and

(iii) beginning and including October 1, 2009, on all Cash Outlays, an amount equal to the amount of such Cash Outlay to prepay outstanding Loans in accordance with Section 2.10(e).

(b)           Section 2.10(e) of the Credit Agreement is hereby amended and restated as follows:

(e)           The Borrower shall deliver to the Administrative Agent, at the time of each prepayment required under this Section 2.10 or any voluntary prepayment under Section 2.10(f), (i) a certificate signed by a Financial Officer of the Borrower, setting forth in reasonable detail the calculation of the amount of such prepayment, including, to the extent applicable, all accrued and unpaid interest under subsection (f) herein; and (ii) to the extent practicable, at least three Business Days prior written notice of such prepayment. Each notice of prepayment shall specify the prepayment date and the principal amount of each Loan (or portion thereof) to be prepaid. All prepayments of Loans under this Section 2.10 shall be accompanied by (i) accrued and unpaid interest (at the Deferral Interest Rate, if applicable) on the principal amount to be prepaid to but excluding the date of payment and (ii) the applicable Payment Premium.  In the event of a prepayment made under subsections 2.10(a)(i) or 2.10(a)(ii), the certificate signed by a Financial Officer of the Borrower shall also set forth:  (i) the amount of the corresponding Cash Outlay, (ii) the amount of the aggregate Cash Outlays to date from December 23, 2008, and (iii) that such Cash Outlay shall only be used to fund the business plan of Holdings.

(c)           Section 2.10(f) is hereby amended and restated as Section 2.10(g) and the following subsection (f) is hereby added to Section 2.10 of the Credit Agreement:

(f)           Beginning and including February 1, 2009, Borrower may defer matching prepayments required under Section 2.10(a) up to an outstanding principal aggregate amount of $5,000,000 (the “ Deferral Facility ”) through April 30, 2009 at which time the outstanding balance of the Deferral Facility shall be paid.  Borrower may make voluntary prepayments (no more frequently than weekly) and re-incur the amount of the Deferral Facility during the above three-month period provided, that at no time shall the aggregate outstanding principal amount of the Deferral Facility exceed $5,000,000.  All outstanding balances on the Deferral Facility shall bear interest (computed on the basis of the actual number of days elapsed over a year of 360 days) at a rate per annum equal to the Adjusted LIBO Rate plus the Applicable Margin plus an additional 2.0% per annum (the “ Deferral Interest Rate ”).  In order to exercise the Deferral Facility, the Borrower shall deliver to the Administrative Agent, at least three Business Days prior written notice of such exercise, which notice of exercise shall specify the date the related Cash Outlay is to be made and the amount of the prepayment otherwise required in connection with the Cash Outlay which is being deferred.  The calculation of the Deferral Interest Rate shall be subject to the provisions of Section 2.20.

(d)           Section 5.13 is hereby amended by adding the following sentences to the end of that section:

Not more than 10 days after the earlier of (i) notice thereof from one of more of the Lenders to Holdings and (ii) knowledge thereof of Holdings, that the aggregate amount of the outstanding shares of common stock of Holdings was greater than 166,445,972 as of the First Amendment Effective Date, Holdings shall deliver incremental warrants, on substantially the same terms as the warrants dated the First Amendment Effective Date, to the Lenders or their designees and permitted assigns exercisable for such number of shares of common stock as necessary for the Lenders or their designees or permitted assigns, as applicable, to hold warrants exercisable for shares of common stock that, in the aggregate, equal 3% of the actual aggregate number of shares of common stock outstanding as of the First Amendment Effective Date.  Until the incremental warrants are delivered in accordance with the preceding sentence, Borrower shall not be permitted to make any Cash Outlays.

Section 3.                       Amendment of Section 6.04 and Section 6.06 of the Credit Agreement .  Section 6.04 and Section 6.06 of the Credit Agreement are hereby amended by adding the following provision to the end of each section:

Notwithstanding Section 5.08 or anything else to the contrary herein, from the First Amendment Effective Date, all distributions (including for purposes of payments under the Management Agreement) made by the Borrower to any holder of Equity Interests of Borrower (other than any Permitted Distributions/Loans and payments permitted under Sections 6.06(a)(ii) and (iii)), and all intercompany loans to, or other Investments in, Holdings or any other Subsidiary made by Borrower, constituting the aggregate Cash Outlays referenced in Section 2.10(a), may only be made by Borrower no more frequently than weekly.  Furthermore, all Cash Outlays referenced in subsections 2.10(a)(i) and 2.10(a)(ii), may only be used to fund the business plan of Holdings.

Section 4.                       Amendment of Section 6.16 of the Credit Agreement .  Section 6.16 of the Credit Agreement is hereby amended and restated as follows:

Section 6.16        Minimum Liquidity Threshold .  At all times after the Closing Date Borrower shall maintain an amount of unencumbered (other than pursuant to the Security Documents) cash on deposit (or in Permitted Investments) on any day including the Maturity Date of at least $7,500,000  (the “ Minimum Liquidity Threshold ”); provided however that solely duri