LANXESS Solutions US (CEMJQ) 8-K Crompton Completes Formation of Joint Venture In Polymer Processing Equipment

                                                    NEWS

CONTACTS:

Investors:
Media: William Kuser
Mary Ann Dunnell (203) 573-2213
(203) 573-3034

CROMPTON ANNOUNCES EXPIRATION OF HART-SCOTT-RODINO WAITING
PERIOD IN PROPOSED MERGER WITH GREAT LAKES CHEMICAL

MIDDLEBURY, CT - April 29, 2005 - Crompton Corporation (NYSE: CK) today
announced that the waiting period under the Hart-Scott-Rodino Antitrust Improvements
Act of 1976 relating to its proposed merger with Great Lakes Chemical Corporation
(NYSE: GLK) has expired.

Approval of the transaction by European competition authorities is still pending.

Crompton Corporation, with 2004 sales of $2.5 billion, is a producer and marketer of
specialty chemicals and polymer products and equipment. Additional information
concerning Crompton Corporation is available atwww.cromptoncorp.com.