EXHIBIT 21 NATIONAL SERVICE INDUSTRIES, INC. LIST OF SUBSIDIARIES <Table> <Caption> STATE OR OTHER JURISDICTION OF INCORPORATION OR SUBSIDIARY OR AFFILIATE PRINCIPAL LOCATION ORGANIZATION - ----------------------- ------------------ ------------------- C&G Carandini S.A. ................................ Barcelona, Spain Spain Castlight de Mexico, S.A. de C.V. ................. Matamoros, Tamaulipas Mexico Graham International B.V. ......................... Bergen op Zoom, Holland The Netherlands Holophane Alumbrado Iberica SRL.................... Barcelona, Spain Spain Holophane Canada, Inc. ............................ Brampton, Ontario Canada Holophane Europe Ltd. ............................. Milton Keynes, England United Kingdom Holophane Lichttechnik G.m.b.H. ................... Dusseldorf, Germany Germany Holophane Lighting Ltd. ........................... Milton Keynes, England United Kingdom Holophane Market Development Corp. ................ Grand Cayman, Cayman Islands Cayman Islands Holophane S.A. de C.V. ............................ Tultitlan, Mexico City Mexico HSA Acquisition Corporation........................ Columbus, Ohio Ohio ID Limited......................................... Douglas, Isle of Man Isle of Man KEM Europe B.V. ................................... Bergen op Zoom, Holland The Netherlands KEPLIME Ltd. ...................................... London, England United Kingdom L & C Funding, Inc. ............................... Atlanta, Georgia Delaware L & C Lighting Group, Inc. ........................ Atlanta, Georgia Delaware L & C Spinco, Inc. ................................ Atlanta, Georgia Delaware LHP Enterprises, Inc. ............................. Atlanta, Georgia Delaware Lithonia Lighting de Mexico S.A. de C.V. .......... Monterrey, Nuevo Leon Mexico Lithonia Lighting do Brasil Ltda................... Sao Paulo, Brazil Brazil Lithonia Lighting Servicios S.A. de C.V. .......... Monterrey, Nuevo Leon Mexico Luxfab Limited..................................... Milton Keynes, England United Kingdom National Airline Laundry Service, LLC.............. Atlanta, Georgia Delaware National Service Industries Canada L.P. ........... Calgary, Alberta Canada National Service Industries, Inc. ................. Atlanta, Georgia California (fka NSI Enterprises, Inc.) National Service Industries, Inc. Chile Ltda....... Santiago, Chile Chile NSI Export Ltd. ................................... Bridgetown, Barbados Barbados NSI Holdings, Inc. ................................ Montreal, Quebec Canada NSI Insurance (Bermuda) Ltd. ...................... Hamilton, Bermuda Bermuda NSI Leasing, Inc. ................................. Atlanta, Georgia Delaware Productos Lithonia Lighting de Mexico, S.A. de C.V. ............................................ Monterrey, Nuevo Leon Mexico Selig Company of Puerto Rico, Inc. ................ Atlanta, Georgia Puerto Rico The Zep Group, Inc. ............................... Atlanta, Georgia Delaware ZEP Belgium S.A. .................................. Brussels, Belgium Belgium Zep Enterprises, Inc. ............................. Atlanta, Georgia Delaware ZEP Europe B.V. ................................... Bergen op Zoom, Holland The Netherlands ZEP Industries Europa B.V. ........................ Bergen op Zoom, Holland The Netherlands ZEP Industries S.A. ............................... Bern, Switzerland Switzerland ZEP Italia S.R.L. ................................. Aprilia, Italy Italy ZEP KEM Italia S.R.L. ............................. Aprilia, Italy Italy ZEP Manufacturing B.V. ............................ Bergen op Zoom, Holland The Netherlands </Table> 66