**Exhibit31.2**

** **

I, Karen R. Osar, certifythat:

 

1.                                           Ihave reviewed this annual report on Form 10-K of Chemtura Corporation;

 

2.                                           Basedon my knowledge, this annual report does not contain any untrue statement of amaterial fact or omit to state a material fact necessary to make the statementsmade, in light of the circumstances under which such statements were made, notmisleading with respect to the period covered by this annual report;

 

3.                                           Basedon my knowledge, the financial statements, and other financial informationincluded in this annual report, fairly present in all material respects thefinancial condition, results of operations and cash flows of the registrant asof, and for, the periods presented in this annual report;

 

4.                                           Theregistrant’s other certifying officer(s) and I are responsible for establishingand maintaining disclosure controls and procedures (as defined in Exchange ActRules 13a-15(e) and 15d-15(e)) andinternal control over financial reporting (as defined in Exchange Act Rules13a-15(f) and 15d-15(f)) for the registrant and have:

 

a)                  Designedsuch disclosure controls and procedures, or caused such disclosure controls andprocedures to be designed under our supervision, to ensure that materialinformation relating to the registrant, including its consolidatedsubsidiaries, is made known to us by others within those entities, particularlyduring the period in which this annual report is being prepared;

 

b)                 Designed such internal control over financialreporting, or caused such internal control over financial reporting to bedesigned under our supervision, to provide reasonable assurance regarding thereliability of financial reporting and the preparation of financial statementsfor external purposes in accordance with generally accepted accountingprinciples;

 

c)                  Evaluated theeffectiveness of the registrant’s disclosure controls and procedures andpresented in this annual report our conclusions about the effectiveness of thedisclosure controls and procedures, as of the end of the period covered by thisannual report based on such evaluation; and

 

d)                 Disclosed in thisannual report any change in the registrant’s internal control over financialreporting that occurred during the registrant’s most recent fiscal quarter (theregistrant’s fourth fiscal quarter in the case of an annual report) that hasmaterially affected, or is reasonably likely to materially affect, theregistrant’s internal control over financial reporting; and

 

5.                   The registrant’sother certifying officer(s) and I have disclosed, based on our most recentevaluation of internal control over financial reporting, to the registrant’sauditors and the audit committee of the registrant’s board of directors (orpersons performing the equivalent functions):

 

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a)                  All significantdeficiencies and material weaknesses in the design or operation of internalcontrol over financial reporting which are reasonably likely to adverselyaffect the registrant’s ability to record, process, summarize and reportfinancial information; and

 

b)                 Any fraud,whether or not material, that involves management or other employees who have asignificant role in the registrant’s internal control over financial reporting.

 

 
| Date: March 31, 2006 |
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|                 |
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| By:                  |  /s/ Karen R. Osar |   |
|                 | Karen R. Osar |
|                 | Executive  Vice President and Chief Financial Officer |

 

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