EXHIBIT21

W. R. GRACE & CO., a Delaware corporationU.S.SUBSIDIARIES

12/31/2005

|         |                                        |
|---------|----------------------------------------|
| X  | Chapter11 Filing — April  2,2001 |

|        |  |                                        |  |        |  |                       |  |  |  |  |  |  |  |  |
|--------|--|----------------------------------------|--|--------|--|-----------------------|--|--|--|--|--|--|--|--|
|   |  | SUBSIDIARYNAME                         |  | CO. #  |  | STATE OFINCORPORATION |
| X      |  | A-1Bit & Tool Co.,Inc.             |  | 458    |  | DE                    |
|   |  | * Advanced Refining TechnologiesLLC    |  | 930    |  | DE                    |
| X      |  | AlewifeBoston Ltd.                     |  | 070    |  | MA                    |
| X      |  | Alewife LandCorporation                |  | 069    |  | MA                    |
|   |  | AlltechAssociates,Inc.                 |  |   |  | IL                    |
| X      |  | Amicon,Inc.                            |  | 174    |  | DE                    |
|   |  | AP ChemIncorporated                    |  | 436    |  | MD                    |
| X      |  | CBBiomedical,Inc.                      |  | 125    |  | DE                    |
| X      |  | CCHP,Inc.                              |  | 074    |  | DE                    |
| X      |  | Coalgrace,Inc.                         |  | 824    |  | DE                    |
| X      |  | CoalgraceII,Inc.                       |  | 835    |  | DE                    |
|   |  | ConstructionProducts Dubai,Inc.        |  | 121    |  | DE                    |
| X      |  | CreativeFood 'N FunCompany             |  | 587    |  | DE                    |
| X      |  | DarexPuerto Rico,Inc.                  |  | 798    |  | DE                    |
| X      |  | Del TacoRestaurants,Inc.               |  | 557    |  | DE                    |
| X      |  | Deweyand Almy,LLC                      |  | 406    |  | DE                    |
| X      |  | Ecarg,Inc.                             |  | 519    |  | NJ                    |
| X      |  | FiveAlewife BostonLtd.                 |  | 071    |  | MA                    |
| X      |  | G CLimited Partners I,Inc.             |  | 465    |  | DE                    |
| X      |  | G CManagement,Inc.                     |  | 539    |  | DE                    |
| X      |  | GECManagementCorporation               |  | 689    |  | DE                    |
| X      |  | GNHoldings,Inc.                        |  | 073    |  | DE                    |
| X      |  | GPCThomasvilleCorp.                    |  | 637    |  | DE                    |
| X      |  | GloucesterNew Communities Company,Inc. |  | 572    |  | NJ                    |
| X      |  | GraceA-BInc.                           |  | 625    |  | DE                    |
| X      |  | GraceA-B II Inc.                       |  | 827    |  | DE                    |
|   |  | GraceAsia Pacific,Inc.                 |  | 107    |  | DE                    |
|   |  | GraceChemicals,Inc.                    |  | 710    |  | DE                    |
| X      |  | GraceChemical Company ofCuba           |  | 305    |  | IL                    |
|   |  | GraceCollections,Inc.                  |  | 316    |  | DE                    |
| X      |  | GraceCulinary Systems,Inc.             |  | 479    |  | MD                    |
| X      |  | GraceDrillingCompany                   |  | 877    |  | DE                    |
| X      |  | GraceEnergy Corporation                |  | 681    |  | DE                    |
|        |

|  |
|--|

|   |                                                                                                                                                                                                   |
|---|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| * | Ownershipof Advanced Refining Technologies LLC is 55% W. R. Grace &Co.-Conn. (#001) and 45% Chevron USA, Inc.; certain enumeratedactions of the Executive Committee require unanimousconsent. |

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|        |  |                                           |  |                |  |                       |  |  |  |  |  |  |  |  |
|--------|--|-------------------------------------------|--|----------------|--|-----------------------|--|--|--|--|--|--|--|--|
|   |  | SUBSIDIARYNAME                            |  | CO. #          |  | STATE OFINCORPORATION |
| X      |  | GraceEnvironmental,Inc.                   |  | 198            |  | DE                    |
| X      |  | GraceEurope, Inc.                         |  | 407            |  | DE                    |
|   |  | GraceGermany Holdings,Inc.                |  |           |  | DE                    |
| X      |  | Grace H-GInc.                             |  | 506            |  | DE                    |
| X      |  | GraceH-G IIInc.                           |  | 828            |  | DE                    |
| X      |  | GraceHotel ServicesCorporation            |  | 480            |  | DE                    |
| X      |  | GraceInternational Holdings,Inc.          |  | 543            |  | DE                    |
|   |  | Grace LatinAmerica, Inc.                  |  | 263            |  | DE                    |
|   |  | GraceManagement Services,Inc.             |  | 485            |  | DE                    |
| X      |  | GraceOffshoreCompany                      |  | 822            |  | LA                    |
| X      |  | GracePARCorporation                       |  | 621            |  | DE                    |
| X      |  | GracePetroleum LibyaIncorporated          |  | 880            |  | DE                    |
|   |  | GraceReceivables Purchasing,Inc.          |  | 041            |  | DE                    |
| X      |  | GraceTarpon Investors,Inc.                |  | 462            |  | DE                    |
| X      |  | GraceVenturesCorp.                        |  | 664            |  | DE                    |
| X      |  | GraceWashington,Inc.                      |  | 197            |  | DE                    |
| X      |  | W. R.Grace CapitalCorporation             |  | 563            |  | NY                    |
| X      |  | W.R. Grace &Co.-Conn.                 |  | 001            |  | CT                    |
| X      |  | W.R. Grace LandCorporation                |  | 523            |  | NY                    |
| X      |  | Gracoal,Inc.                              |  | 856            |  | DE                    |
| X      |  | GracoalII,Inc.                            |  | 848            |  | DE                    |
| X      |  | Guanica-CaribeLand DevelopmentCorporation |  | 376            |  | DE                    |
| X      |  | HanoverSquareCorporation                  |  | 516            |  | DE                    |
| X      |  | HomcoInternational,Inc.                   |  | 631            |  | DE                    |
|   |  | IchibanChemical Co.,Inc.                  |  | 028            |  | DE                    |
| X      |  | KootenaiDevelopmentCompany                |  | 779(f/k/a 079) |  | MT                    |
| X      |  | L B Realty,Inc.                           |  | 495            |  | DE                    |
| X      |  | LitigationManagement,Inc.                 |  | 317            |  | DE                    |
| X      |  | MonolithEnterprises,Incorporated          |  | 477            |  | DC                    |
| X      |  | MonroeStreet,Inc.                         |  | 481            |  | DE                    |
| X      |  | MRAHoldingsCorp.                          |  | 075            |  | DE                    |
| X      |  | MRAIntermedco,Inc.                        |  | 076            |  | DE                    |
| X      |  | MRAStaffing Systems,Inc.                  |  | 077            |  | DE                    |
|   |  | NZ Alltech,Inc.                           |  |           |  | IL                    |
| X      |  | RemediumGroup,Inc.                        |  | 063            |  | DE                    |
| X      |  | SouthernOil, Resin & Fiberglass,Inc.  |  | 318            |  | FL                    |
| X      |  | WaterStreetCorporation                    |  | 548            |  | DE                    |
|        |

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NON-U.S.SUBSIDIARIES

|                                               |  |  |
|-----------------------------------------------|--|--|
| **COUNTRY/SUBSIDIARYNAME**                    |
| **ARGENTINA**                                 |
| W.R. Grace Argentina S.A.                     |
| WRG Argentina,S.A.                            |
| **AUSTRALIA**                                 |
| AlltechAssociates (Australia) Pty. Ltd.       |
| Grace AustraliaPty. Ltd.                      |
| **BELGIUM**                                   |
| GraceConstruction Products N.V.               |
| GraceN.V.                                     |
| Grace Silica N.V.                             |
| InvercoBenelux N.V.                           |
| **BRAZIL**                                    |
| GraceBrasil Ltda.                             |
| Grace DavisonLtda.                            |
| **CANADA**                                    |
| GECDivestment Corporation Ltd.                |
| Grace Canada,Inc.                             |
| W. R. Grace Finance (NRO)Ltd.                 |
| **CHILE**                                     |
| Grace QuimicaCompania Limitada                |
| **CHINA — PEOPLE’SREPUBLIC OF**   |
| Grace ChinaLtd.                               |
| **COLOMBIA**                                  |
| GraceColombia S.A.                            |
| W. R. G. ColombiaS.A.                         |
| **CUBA**                                      |
| EnvasesIndustriales y Comerciales, S.A.       |
| PapeleraCamagueyana,S.A.                      |
| **FRANCE**                                    |
| Alltech FranceS.A.R.L.                        |
| Etablissements PieriS.A.                      |
| Société CivileBeau-Béton |
| W. R. Grace S.A.                              |
| **GERMANY**                                   |
| Advanced RefiningTechnologies GmbH            |
| Alltech GromGmbH                              |
| Grace Bauprodukte GmbH                        |
| GraceDarex GmbH                               |
| Grace GPG.m.b.H.                              |
| **GERMANY(Continued)**                        |
| Grace HoldingG.m.b.H.                         |
| Grace Management GPG.m.b.H.                   |
| Grace SilicaGmbH                              |
|                                               |

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|                                                    |  |  |
|----------------------------------------------------|--|--|
| **COUNTRY/SUBSIDIARYNAME**                         |
| **GREECE**                                         |
| GraceHellas E.P.E.                                 |
| **HONGKONG**                                       |
| Alltech Applied Science Labs (HK)Limited           |
| Alltech Scientific (China)Limited                  |
| W. R. Grace (Hong Kong)Limited                     |
| W. R. Grace Southeast Asia HoldingsLimited         |
| **HUNGARY**                                        |
| GraceÉrtékesitoKft.                  |
| **INDIA**                                          |
| FlexitLaboratories Private Ltd.                    |
| W. R. Grace & Co.(India) PrivateLimited        |
| **INDONESIA**                                      |
| PT.Grace Specialty ChemicalsIndonesia              |
| **IRELAND**                                        |
| AmiconIreland Limited                              |
| Grace Construction Products(Ireland) Limited       |
| Trans-Meridian Insurance (Dublin)Ltd.              |
| **ITALY**                                          |
| Alltech ItaliaS.R.L.                               |
| W. R. Grace ItalianaS.p.A.                         |
| **JAPAN**                                          |
| AdvancedRefining Technologies K.K.                 |
| Grace ChemicalsK.K.                                |
| Grace Japan KabushikiKaisha                        |
| **KOREA**                                          |
| Grace KoreaInc.                                    |
| **MALAYSIA**                                       |
| W. R. Grace(Malaysia) Sendiran Berhad              |
| W. R. Grace SpecialtyChemicals (Malaysia) Sdn.Bhd. |
| **MEXICO**                                         |
| GraceContainer, S. A. de C. V.                     |
| W. R. Grace Holdings, S.A. de C.V.                 |
| **NETHERLANDS**                                    |
| AlltechApplied Science B.V.                        |
| AmiconB.V.                                         |
| Denac Nederland B.V.                               |
| Stormvan Bentem en Kluyver B.V.                    |
| W. R. GraceB.V.                                    |
| **NETHERLANDSANTILLES**                            |
| W. R. GraceN.V.                                    |
| **NEW ZEALAND**                                    |
| Grace(New Zealand) Limited                         |
|                                                    |

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|                                                |  |  |
|------------------------------------------------|--|--|
| **COUNTRY/SUBSIDIARYNAME**                     |
| **PHILIPPINES**                                |
| W.R. Grace (Philippines),Inc.                  |
| **POLAND**                                     |
| Grace Sp. zo.o.                                |
| **RUSSIA**                                     |
| Darex CISLLC                                   |
| **SINGAPORE**                                  |
| W. R. Grace(Singapore) Private Limited         |
| **SOUTHAFRICA**                                |
| Grace Davison (Proprietary)Limited             |
| W. R. Grace Africa (Pty.)Limited               |
| **SPAIN**                                      |
| Grace,S.A.                                     |
| Pieri Especialidades,S.L.                      |
| **SWEDEN**                                     |
| GraceAB                                        |
| Grace Catalyst AB                              |
| Grace SwedenAB                                 |
| **SWITZERLAND**                                |
| PieriS.A.                                      |
| **TAIWAN**                                     |
| W. R. GraceTaiwan, Inc.                        |
| **THAILAND**                                   |
| W.R. Grace (Thailand) Limited                  |
| **UNITEDKINGDOM**                              |
| A.A. Consultancy & Cleaning CompanyLimited |
| Alltech Associates Applied ScienceLimited      |
| Cormix Limited                                 |
| Borndear 1Limited                              |
| Borndear 2Limited                              |
| Borndear 3 Limited                             |
| DarexUK Limited                                |
| Emerson & Cuming (Trading)Ltd.             |
| Emerson & Cuming (UK)Ltd.                  |
| Exemere Limited                                |
| GraceConstruction Products Limited             |
| Pieri U.K.Limited                              |
| Servicised Ltd.                                |
| W. R.GraceLimited                              |
| **VENEZUELA**                                  |
| GraceVenezuela, S.A.                           |
| Inversiones GSC,S.A.                           |
|                                                |

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