H2M Group Labs, Inc. - NY, USA

H2NS Environmental - TX, USA

Hach Company - CO, USA

Halla Engineering & Ind'l. Dev. Co. - KOREA

Hamilton Sunstrand Appl.Instr.Tech. - CA, USA

Harding ESE - FL, USA

Harding ESE - IL, USA

Harding Lawson Associates - IL, USA

Harding Lawson Associates - ME, USA

Haskoning/Div. of Envr.Affairs - NETHERLANDS

HAZCO Services, Inc. - OH, USA

HDN-Technik mbH - GERMANY

HDR Engineering, Inc. - NE, USA

Headline Filters GmbH - GERMANY

Herion-Werke KG - GERMANY

Hewlett-Packard Co./Anal.Mktg. - DE, USA

Hillesheim GmbH - GERMANY

Hi-Q Environmental Products Co. - CA, USA

HMM Associates - MI, USA

HNU Systems, Inc. - MA, USA

HNU Systems,(Canada)Ltd. - CANADA

HNU-Nordion Ltd. Oy - FINLAND

Hobre Instruments BV - NETHERLANDS

Honeywell Microtrac - TX, USA

Honeywell PAI/Process Analysts,Inc. - CO, USA

Horiba Europe GmbH - GERMANY

Horiba Instruments, Inc. - CA, USA

Horiba Ltd. - JAPAN

Houston Atlas, Inc. - TX, USA

Hull Company/SP Indust.Co. - PA, USA

Hund GmbH - GERMANY

Hunter Environmnt'l.Srvcs.,Inc - CT, USA

Huntingdon Engr.& Environmnt'l - TX, USA

Hygenius, Inc. - CANADA