Offer to Purchase for Cash

                     All Outstanding Shares of Common Stock

           (Including the Associated Preferred Share Purchase Rights)

                                       of

                                  CHIREX INC.

                                       at

                          $31.25 Net Per Share in Cash

                                       by

                            COUSIN ACQUISITION, INC.

                     an indirect wholly owned subsidiary of

                                     RHODIA

 THE OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT 12:00 MIDNIGHT, NEW YORK
 CITY TIME, ON THURSDAY, AUGUST 31, 2000, UNLESS THE OFFER IS EXTENDED.

                                                                  August 4, 2000

To Brokers, Dealers, Commercial Banks,
    Trust Companies and Other Nominees:

   We have been appointed by Cousin Acquisition, Inc., a Delaware corporation
("Purchaser") and an indirect wholly owned subsidiary of Rhodia, a French
corporation ("Parent"), to act as Dealer Manager in connection with Purchaser's
offer to purchase all the issued and outstanding shares of common stock, par
value $.01 per share ("Common Shares") of ChiRex Inc., a Delaware corporation
(the "Company"), together with the associated rights to purchase preferred
shares that are issued pursuant to the Rights Agreement dated as of March 31,
1997 between the Company and The First National Bank of Boston as Rights Agent
(the "Rights" and, together with the Common Shares, the "Shares"), for $31.25
per Share, net to the seller in cash, upon the terms and subject to the
conditions set forth in Purchaser's Offer to Purchase, dated August 4, 2000
(the "Offer to Purchase"), and the related Letter of Transmittal (which,
together with the Offer to Purchase and any amendments or supplements thereto,
collectively constitute the "Offer") enclosed herewith. Please furnish copies
of the enclosed materials to those of your clients for whose accounts you hold
Shares registered in your name or in the name of your nominee.

   The Offer is conditioned upon, among other things, (i) there having been
validly tendered and not withdrawn prior to the expiration of the Offer at
least the number of Shares that, when added to the Shares already owned by
Parent, shall constitute a majority of the then outstanding Shares on a fully
diluted basis (including, without limitation, all Shares issuable upon the
conversion of any convertible securities or upon the exercise of any options,
warrants, or rights), and (ii) any applicable waiting periods under the Hart-
Scott-Rodino Antitrust Improvements Act of 1976, as amended, and the German Law
Against Restraints on Competition, having expired or been terminated prior to
the expiration of the Offer.


   For your information and for forwarding to your clients for whom you hold
Shares registered in your name or in the name of your nominee, we are enclosing
the following documents:

     1. Offer to Purchase, dated August 4, 2000;

     2. Letter of Transmittal for your use in accepting the Offer and
  tendering Shares and for the information of your clients;

     3. Notice of Guaranteed Delivery to be used to accept the Offer if the
  Shares and all other required documents are not immediately available or
  cannot be delivered to Wilmington Trust Company (the "Depositary") prior to
  the Expiration Date (as defined in the Offer to Purchase) or if the
  procedure for book-entry transfer cannot be completed prior to the
  Expiration Date;

     4. A letter to stockholders of the Company from Michael A. Griffith,
  Chairman and Chief Executive Officer of the Company, together with a
  Solicitation/Recommendation Statement on Schedule 14D-9 filed with the
  Securities and Exchange Commission by the Company;

     5. A letter which may be sent to your clients for whose accounts you
  hold Shares registered in your name or in the name of your nominee, with
  space provided for obtaining such clients' instructions with regard to the
  Offer;

     6. Guidelines for Certification of Taxpayer Identification Number on
  Substitute Form W-9; and

     7. Return envelope addressed to the Depositary.

   WE URGE YOU TO CONTACT YOUR CLIENTS AS PROMPTLY AS POSSIBLE. PLEASE NOTE
THAT THE OFFER AND WITHDRAWAL RIGHTS EXPIRE AT 12:00 MIDNIGHT, NEW YORK CITY
TIME, ON THURSDAY, AUGUST 31, 2000, UNLESS THE OFFER IS EXTENDED.

   In all cases, payment for Shares accepted for payment pursuant to the Offer
will be made only after timely receipt by the Depositary of (i) certificates
evidencing such Shares (or a confirmation of a book-entry transfer of such
Shares into the Depositary's account at the Book-Entry Transfer Facility (as
defined in the Offer to Purchase)), (ii) a Letter of Transmittal (or manually
signed facsimile thereof) properly completed and duly executed with any
required signature guarantees or, in the case of a book-entry transfer, an
Agent's Message (as defined in the Offer to Purchase) and (iii) any other
documents required by the Letter of Transmittal.

   If holders of Shares wish to tender, but it is impracticable for them to
forward their certificates or other required documents prior to the expiration
of the Offer, a tender may be effected by following the guaranteed delivery
procedure described in Section 3 of the Offer to Purchase.

   Purchaser will not pay any fees or commissions to any broker, dealer or
other person (other than the Dealer Manager, the Depositary and the Information
Agent as described in the Offer to Purchase) in connection with the
solicitation of tenders of Shares pursuant to the Offer. However, Purchaser
will reimburse you for customary mailing and handling expenses incurred by you
in forwarding any of the enclosed materials to your clients. Purchaser will pay
or cause to be paid any stock transfer taxes payable with respect to the
transfer of Shares to it, except as otherwise provided in Instruction 6 of the
Letter of Transmittal.

   Any inquiries you may have with respect to the Offer should be addressed to
Bear, Stearns & Co. Inc. or MacKenzie Partners, Inc. (the "Information Agent")
at their respective addresses and telephone numbers set forth on the back cover
page of the Offer to Purchase.

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   Additional copies of the enclosed material may be obtained from the
Information Agent, at the address and telephone number set forth on the back
cover page of the Offer to Purchase.

                                          Very truly yours,

                                          [LOGO OF BEAR STEARNS]


   NOTHING CONTAINED HEREIN OR IN THE ENCLOSED DOCUMENTS SHALL CONSTITUTE YOU
OR ANY OTHER PERSON THE AGENT OF PARENT, PURCHASER, THE COMPANY, THE DEALER
MANAGER, THE INFORMATION AGENT OR THE DEPOSITARY, OR OF ANY AFFILIATE OF ANY OF
THE FOREGOING, OR AUTHORIZE YOU OR ANY OTHER PERSON TO USE ANY DOCUMENT OR TO
MAKE ANY STATEMENT ON BEHALF OF ANY OF THE FOREGOING IN CONNECTION WITH THE
OFFER OTHER THAN THE ENCLOSED DOCUMENTS AND THE STATEMENTS CONTAINED THEREIN.

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