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Exhibit 21.01

ATMI, INC.
Subsidiaries

|                                                    |  |                                                       
|--------------------------------------------------- |  | ------------------------------------------------------
|                                                    |  |                                                       
|Entity                                              |  | State or Jurisdiction of Incorporation or Organization
|                                                    |  |                                                       
|Advanced Technology Materials, Inc.                 |  | Delaware                                              
|Epitronics Corporation                              |  | Delaware                                              
|ATMI Ecosys Corporation                             |  | California                                            
|Advanced Delivery & Chemical Systems Nevada, Inc.   |  | Nevada                                                
|Advanced Delivery & Chemical Systems Holdings, LLC  |  | Delaware                                              
|Advanced Delivery & Chemical Systems Operating, LLC |  | Delaware                                              
|Advanced Delivery & Chemical Systems Manager, Inc.  |  | Delaware                                              
|ATMI Materials, Ltd.                                |  | Texas                                                 
|ATMI Korea Co. Ltd.                                 |  | Korea                                                 
|ATMI UK Limited                                     |  | Scotland                                              
|ATMI Fab Services, Inc.                             |  | New Mexico                                            
|ATMI Fab Services Ireland, Inc.                     |  | New Mexico                                            
|MST Measurement Systems, Inc.                       |  | Illinois                                              
|ATMI Packaging, Inc.                                |  | Minnesota                                             
|ATMI Packaging International Ltd.                   |  | Minnesota                                             
|NOW Japan Branch                                    |  | Japan                                                 
|ATMI International Holdings, Inc.                   |  | Delaware                                              
|ATMI Taiwan Holdings, Inc.                          |  | Delaware                                              
|ATMI Belgium Holdings, Inc.                         |  | Delaware                                              
|ATMI Belgium, LLC                                   |  | Delaware                                              
|Emosyn LLC                                          |  | Delaware                                              
|Newform, N.V.                                       |  | Belgium                                               
|ATMI Japan Branch                                   |  | Japan                                                 
|ATMI Taiwan Co. Ltd.                                |  | Taiwan                                                
|ATMI GmbH                                           |  | Germany                                               
|Advanced Technology Materials FSC, Inc.             |  | Barbados                                              
|ATMI PTE Ltd                                        |  | Singapore                                             
|Phoenix 2002 Liquidating LLC                        |  | Delaware