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Est. 1954 · Cleves, Ohio · 100% Employee-Owned
Seventy Years, Told in Full.
The short version lives on our About Us page. This is the complete one — the shop that started it, the years the Tisch name wasn't on the door, and where we're headed from here.
100%Employee Owned
72+Years of Expertise
4Generations Involved
USAMade in Ohio
Chapter 01
1954 – 1968
The Shop That Started It
In 1954, Web Tisch bought a small sheet metal shop in Greendale, Indiana called General Metal Works (GMW). There was no plan to build air quality instrumentation. GMW fabricated what customers needed: enclosures, brackets, blower housings.
One of those customers was the United States Department of Public Health Service. Working with Dr. Fodor on government-issued specifications, GMW's shop built the first Total Suspended Particulate (TSP) High Volume Air Sampler: the Model 2000. It became the industry's first real standard for measuring particulate matter in open air.
Through the late 1950s and 1960s, GMW kept building on that foundation, fabricating stainless steel filter holders and blower motor assemblies at a pace that outgrew the original shop. By 1965, the Air Sampling Division split off as its own operation, led by Web's son, Wilbur (Will) Tisch, who pushed the instrumentation further even as competitors entered the field.
GMW wasn't chasing an industry. It was answering a government spec well enough that the government kept coming back.
Chapter 02
1970 – 1998
The Years the Name Left Cleves
The 1970s and '80s were a period of real growth. In 1970, GMW introduced the aluminum shelter for field air samplers, the same year the U.S. Environmental Protection Agency was formed. That same year, GMW purchased the old Avalon Theater and converted it into a production facility. By 1980, a neighboring butcher shop and a new high bay building were added to keep pace with demand.
Then, in 1983, GMW was acquired by Andersen Instruments — the first time the business changed hands outside the family. It wasn't the last. Through the 1990s, ownership transferred several more times, and late in the decade, Thermo Environmental relocated production to Atlanta, Georgia, laying off local staff in the process. For a stretch, it looked like the Cleves chapter of this story was closed for good.
It wasn't. In 1998, W. John Tisch and Jim Tisch founded Tisch Environmental, Inc. (TEI), bringing precision air sampling manufacturing back to the family, and back home.
We don't leave this part out. It's the reason "employee-owned" and "family-led" mean something specific to us today: we know exactly what it looks like to lose that, and what it took to get it back.
1954–1983
Family-Led
General Metal Works
Founded and run by Web, then Wilbur (Will) Tisch.
1983
Acquired
Andersen Instruments
GMW is acquired. Ownership leaves the family for the first time.
1980s–90s
Transferred
Multiple Transfers
Ownership passes through several hands over the decade.
Late 1990s
Relocated
Thermo Environmental
Production relocates to Atlanta, GA. Local staff are laid off.
1998
Family-Led
Tisch Environmental, Inc.
W. John and Jim Tisch found TEI, independent and family-led again.
Chapter 03
1998 – 2014
Rebuilding, Then Diversifying
With TEI re-established in Cleves, the focus shifted from survival to growth. In 2000, the company acquired AADCO Instruments, adding a Zero Air Generator (ZAG) line and diversifying beyond air sampling equipment for the first time. In 2002, TEI earned its first Federal Reference Method (FRM) designation from the U.S. EPA, for the 6XXX series PM10 high-volume monitor — a formal, regulatory stamp of approval that international customers could trust.
As demand for replacement filters grew alongside the equipment business, TEI launched a dedicated division in 2007: Tisch Scientific, focused on reselling high-quality filtration and lab products. The timing lined up well: in 2008, EPA regulation added lead (Pb) back to the criteria pollutant list, reviving demand for high-volume samplers and the filters that go with them. By 2011, Tisch Scientific had outgrown its space and relocated to a larger facility in North Bend, Ohio.
The chapter closes with one of TEI's proudest moments: in 2014, the company's low-volume sampling platform earned FRM status across three particulate size fractions — PM10, PM2.5, and PMc. The product was named TE-WILBUR, in honor of Wilbur (Will) Tisch. Around the shop, it's still just called "the Wilbur."
2000AADCO Instruments acquired
2002First FRM designation
2007Tisch Scientific formed
2014The Wilbur earns FRM status
Chapter 04
2021 – Today
Where We Stand Today
The most recent chapter moved fast. In 2021, TEI introduced the TE-BC251 bio-aerosol collector, developed in direct response to the COVID-19 pandemic to help capture airborne virus samples. In 2022, Tisch Environmental and Tisch Scientific consolidated operations into a new, 20,000-square-foot facility in Cleves, Ohio, bringing both brands under one roof for the first time.
Then, in 2023, TEI became a 100% employee-owned company through an Employee Stock Ownership Plan (ESOP). After a stretch in the 1980s and '90s where ownership changed hands more times than anyone here would like to count, continuity no longer depends on a single family or a single buyer. Every technician, engineer, and support specialist who builds and ships your equipment now has a direct stake in it.
Today, that means Tisch Scientific alone carries over 5,500 products across biochemistry, environmental regulation, pharmaceutical research, and higher education, while Tisch Environmental continues to manufacture the FRM and FEM instrumentation regulators and researchers rely on, in the same Cleves community where it all started.
Where It Led
One Shop, Three Product Lines
Each of these grew directly out of what came before it. None were part of a five-year plan.
Since 1954
Tisch Environmental
High and low volume air samplers, calibration equipment, and FRM/FEM instrumentation for regulatory and research use.
Browse the product lineSince 2000
Zero Air Generators
Acquired from AADCO Instruments, this line delivers ultra-pure calibration gas and remains part of both Tisch brands today.
See the ZAG lineSince 2007
Tisch Scientific
Started as a response to customers asking for replacement filters. Now a full lab-supply catalog of over 5,500 products.
Visit Tisch Scientific
Chapter 05
Looking Ahead
Where We're Headed
The Legacy Isn't Finished. It's Just Employee-Owned Now.
Seventy-plus years in, the strategic plan hasn't changed much: keep building high-quality air monitoring instrumentation, keep contributing to real improvements in global air quality, and keep the kind of customer service that's been part of this company since Web Tisch answered the phone himself.
What's different is who's responsible for keeping that promise. As a 100% employee-owned company, that job now belongs to every person on the floor, not a single family or a rotating cast of outside owners. Recent launches like the FloCal-30 flow calibrator show that commitment in practice: new engineering, still built and supported out of Cleves, still backed by the same standard the Model 2000 was held to in 1954.
72+ Years, Still Building
Read the Short Version, or Talk to Cleves Directly.
The About Us page has the highlight reel and the team behind it. Or skip straight to a person who can answer your equipment questions.