Manufacturer: Demco Inc. Headquarters: Oklahoma City, Oklahoma Founded: 1945 (as Drilling Equipment Manufacturing Co.; renamed DEMCO in 1965) Documented Asbestos Use: Through approximately the early 1980s (consistent with the industry-wide phase-out) Product Categories: Butterfly valves, wafer valves, and gate valves Legal Status: Tier 2 — Named in asbestos litigation; no dedicated bankruptcy trust identified

Company History

Demco Inc. was established in 1945 in Oklahoma City, Oklahoma, originally under the name Drilling Equipment Manufacturing Co., and built an early reputation for drilling-rig tooling before expanding into flow-control products. With the 1950s introduction of its gate and butterfly valve lines, the company grew rapidly; its high-pressure gate valve for drilling-mud service earned the nickname “the mud valve.” The company adopted the recognizable DEMCO name in 1965. Demco later became part of Gardner-Denver Co. in 1975 and was subsequently incorporated into the Cooper Industries family of products, with the DEMCO valve line continuing under later corporate ownership.

During the mid-twentieth century — roughly the 1950s through the early 1980s — asbestos was a standard material for valve sealing and gasketing throughout the industry. Butterfly valves, wafer valves, and gate valves operated in fluid-handling systems that required reliable seals under pressure, and manufacturers across the industry routinely relied on asbestos-containing gaskets and packing because these materials were regarded at the time as reliable and industry-standard. According to asbestos litigation records, workers who installed or maintained valves of this era were potentially exposed to asbestos-containing components associated with such products.

Demco’s corporate succession — through Gardner-Denver and Cooper Industries — is relevant to individuals researching exposure history, because successor relationships can affect which legal entities may be named in asbestos-related claims.

Asbestos-Containing Products

Demco did not manufacture asbestos as a raw material. According to asbestos litigation records, however, industrial valves of the mid-twentieth century commonly incorporated asbestos-containing sealing components, and plaintiffs have alleged that butterfly, wafer, and gate valves of this type were designed and sold with such materials.

Gaskets were among the components most frequently identified in litigation involving valves of this type. Wafer-style butterfly valves are clamped between pipe flanges, and gaskets create the seal at those flanged connections. During the relevant era, compressed asbestos fiber (CAF) gaskets were standard throughout the valve and piping industry. Plaintiffs have alleged that valves of this era were installed with asbestos-containing gaskets and that replacement gaskets specified for such connections were similarly composed of asbestos-containing materials.

Valve stem packing — also called gland packing — was another component identified in court filings involving comparable valves. Braided or compressed asbestos packing was routinely used to seal the valve stem where it passes through the valve body, preventing leakage around the stem. According to court filings, the hazard associated with these components was not limited to initial installation: gaskets and packing degrade over time and required periodic replacement, and each removal of a worn asbestos-containing gasket or packing set — typically involving scraping, wire-brushing, or cutting — could generate airborne asbestos fibers.

Documented Naval Service

According to U.S. Navy machinery and equipment records, butterfly and wafer valves manufactured by Demco were documented aboard United States Navy vessels, including the aircraft carriers USS Nimitz (CVN-68) and USS Forrestal (CVA-59). This documentation identifies Demco as an original-equipment manufacturer (OEM) of shipboard flow-control valves. Naval valves of this era commonly incorporated asbestos-containing gaskets and stem packing, and — according to asbestos litigation records — pipefitters, machinist’s mates, and shipyard workers who installed, operated, or overhauled this equipment may have encountered asbestos-containing components during service and maintenance.

Occupational Exposure

According to asbestos litigation records, exposure to asbestos-containing components associated with valves of this type occurred across a range of industrial and maritime occupations. The following worker categories appear with regularity in asbestos claims involving comparable equipment:

Pipefitters and Plumbers who installed valves into piping systems frequently handled gaskets at flanged connections — cutting them to fit, tightening connections, and breaking apart old joints to replace failed gaskets.

Mechanics and Millwrights responsible for maintaining valves were among the most heavily exposed, according to plaintiffs’ allegations. Rebuilding or repacking a valve — extracting worn packing, scraping old gasket material, and reassembling with new components — put these workers in direct, repeated contact with asbestos-containing parts.

Navy Pipefitters, Machinist’s Mates, and Shipyard Workers who maintained shipboard valves in engine rooms, fire rooms, and auxiliary machinery spaces are documented in asbestos litigation records involving marine valve equipment.

Oilfield, Refinery, and Chemical Plant Workers who installed and maintained Demco valves in drilling, petroleum-transfer, and process applications may also have encountered asbestos-containing gaskets and packing during valve service.

Bystander and Secondary Exposure — Workers in proximity to gasket and packing work could also be exposed, as fibers released during such work can travel through a work area.

The period of heaviest documented exposure corresponds approximately to the 1950s through the early 1980s, consistent with the broader industrial use of asbestos before regulatory action by OSHA and the EPA prompted a significant reduction in asbestos use. Use of asbestos-containing components in industrial valves of this class is understood to have been phased out industry-wide by approximately the early 1980s.

It should be noted that the latency period for asbestos-related diseases — including mesothelioma, asbestosis, and asbestos-related lung cancer — is typically between 20 and 50 years following initial exposure.

Demco Inc. is classified as a Tier 2 manufacturer for purposes of this reference site. This designation means the company has been named in asbestos-related personal injury litigation, but no dedicated asbestos bankruptcy trust fund has been identified for it. Accordingly, claims involving Demco valves would be pursued through direct civil litigation rather than a trust claims process.

Plaintiffs have alleged in asbestos cases that valves of this type incorporated asbestos-containing gaskets and packing. Whether and to what degree the company or its successors have faced adverse judgments, settlements, or other litigation outcomes varies by case; this article does not represent any specific outcome as established legal fact.

Because Demco has operated through corporate relationships — including its association with Gardner-Denver and Cooper Industries — individuals pursuing legal claims may need to account for corporate succession when identifying appropriate defendants. For individuals also exposed to asbestos-containing products from other manufacturers — a common circumstance in industrial, oilfield, and shipboard environments — separate trust fund claims may be available through those manufacturers’ established asbestos trusts.

If you or a family member worked with or around Demco butterfly, wafer, or gate valves during the 1950s through the early 1980s and has since been diagnosed with mesothelioma, asbestosis, or asbestos-related lung cancer, legal options may be available.

Key points to understand:

  • Demco has been named in asbestos litigation but does not appear to operate a dedicated asbestos bankruptcy trust fund. Claims would be pursued through direct civil litigation.
  • Corporate succession involving Gardner-Denver and Cooper Industries may be relevant to identifying proper defendants.
  • Workers exposed to multiple asbestos-containing products — as was common aboard Navy ships, in shipyards, and in industrial plants — may be eligible to file claims against multiple responsible parties, including manufacturers with established trust funds.
  • The long latency period for asbestos-related disease means that exposure from decades ago can give rise to claims today.
  • Documentation of your work history — including employers, ships or job sites, job titles, and any product names or model numbers you can recall — is valuable when consulting with an attorney and should be preserved.

An attorney specializing in asbestos litigation can review your work history, identify relevant products and manufacturers, and advise on available legal remedies.

This reference article is provided for informational purposes to workers, families, and legal professionals researching asbestos exposure history. It does not constitute legal advice. Product identification and litigation history are drawn from publicly available records and reflect allegations, not findings of liability, which is determined case by case.