USS Impervious (MSO-449) — Equipment Manifest & Asbestos Exposure Record
Documented equipment manifest and asbestos exposure record for USS Impervious (MSO-449), a Aggressive-class ocean minesweeper in service 1954–1991. 15...
By Rights Watch Media Group LLC•June 6, 2026•3 min read
Shipyard, deployment, and service events for this vessel documented in the public record — court filings, the ship’s deck logs, or the crew’s own cruise book (each entry cites its source). Dry-dockings, overhauls, and yard periods were when asbestos insulation was torn out and replaced, the peak-exposure work for the crew and yard workers aboard.
1957
Yard period / shipyard · Long BEACH — In the shipyard at Long BEACH, per the ship's deck log.
Derived from publicly filed asbestos-litigation records, ship’s deck logs, and the crew’s own cruise books. Historical service events; this does not constitute legal or medical advice.
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USS Impervious (MSO-449) underway on the Potomac River, Washington D.C. (USA), on 7 July 1990 (6457729)Source: Wikimedia Commons — public domain (U.S. Navy photograph)
Service History
From the public Wikipedia / DANFS service-history record — source ›
USS Impervious (MSO-449) was an Agile-class minesweeper commissioned in 1954 and homeported at Long Beach, California, where she conducted multiple Far East deployments with the U.S. 7th Fleet throughout the 1950s and 1960s, including training operations with allied navies in the western Pacific and support missions off Vietnam. In 1990-1991, she was transported to the Persian Gulf for Operation Desert Storm, where she participated in mine countermeasures operations to clear navigation routes and provided escort support for damaged vessels including USS Tripoli (LPH-10), which struck an Iraqi mine on 18 February 1991. The ship's service record reflected her primary role in mine warfare and regional security operations during the Cold War and immediate post-Cold War era.
Construction & Service Dates
Builder
Martinolich Shipbuilding Co., San Diego, California
Launched
1952-08-29
Commissioned
1954-07-15
Notable Tours / Service Eras
Far East deployment 1955-1956
Far East deployment 1958
Far East deployment 1960
Far East deployment 1962
Far East deployment 1964
Persian Gulf War 1990-1991
Combat Actions
Persian Gulf War mine countermeasures operations· 1991-02 minesweeping and escort operations
Home Ports & Forward Bases
Long Beach, California — home port 1955-1964
Norfolk, Virginia — 1990-1991
Drydock & Overhaul Periods
High Asbestos-Exposure Window
Los Angeles, California· 1964-1965 overhaul
Asbestos rip-out, insulation replacement, and gasket-packing work occurred during these yard periods. Sailors aboard during overhauls had peak exposure to airborne asbestos fiber.
Notable Incidents
18 February 1991 — supported USS Tripoli (LPH-10) mine countermeasures operations in Persian Gulf
Read the video transcript
Did you serve aboard the USS Impervious? This minesweeper carried asbestos in nearly every compartment. Here is where it was, and who is responsible. The USS Impervious, hull number MSO-449, was a minesweeper, built by Martinolich Shipbuilding Co. and commissioned in 1954. She served through Far East deployment, Far East deployment, and Far East deployment. Public naval references list this equipment aboard the USS Impervious, MSO-449 — insulated and sealed with asbestos. Each shipyard overhaul and major repair meant asbestos insulation was torn out and replaced — peak-exposure work for the yard workers and the crew aboard. Exposure was worst in the engineering spaces, where the snipes worked — but asbestos lined the whole ship, so all hands were exposed. The companies that made the asbestos equipment aboard — not the Navy — are who asbestos claims are brought against. According to asbestos litigation records, the equipment aboard the USS Impervious from makers such as US Radiator Corp., Westinghouse, Delco, and Hallet Mfg-Westinghouse allegedly contained asbestos. If you served aboard the USS Impervious and were later diagnosed with mesothelioma, asbestosis, or another asbestos-related disease, you may have a legal claim against the companies that made the asbestos products used aboard your ship. This is educational information from an independent publisher — not a law firm — and is not legal advice.
USS Impervious (MSO-449) was an Aggressive-class ocean minesweeper commissioned 15 July 1954 — Vietnam War minesweeping operations and Cold War mine warfare force service through 1991.
The 15-entry equipment manifest below is sourced from ship-specific BUSHIPS (Bureau of Ships) documentation identifying machinery and equipment installed aboard. Each entry is documented equipment with verified manufacturer attribution — primary-source material for asbestos-exposure case development by Navy veterans and surviving families.
Equipment Manifest
Equipment Manifest — USS Impervious (MSO-449). 15 machinery/equipment entries identified through ship-specific BUSHIPS documentation. Manufacturers in bold link to documented asbestos-product history on AsbestosIndex.com.
The standard asbestos-containing materials installed throughout U.S. Navy minesweepers of this era are documented to have included:
Pipe lagging and thermal insulation on main steam, feed-water, fuel-oil, condensate, and saltwater piping throughout machinery spaces
Boiler block insulation, refractory brick, and gun-blocks around the main boilers
Asbestos gaskets and braided packing in valves, flanges, pumps, condensers, heat exchangers, and turbine glands
Insulation jackets and removable lagging on main propulsion turbines, reduction gears, ship-service turbine generators, and forced-draft blowers
Sheet asbestos and Marinite panels as fire-stops, bulkhead insulation, and overhead insulation
Vinyl asbestos floor tile (VAT) in passageways, berthing, mess decks, and habitable compartments
Asbestos rope, wick, and tape in gland-seal applications throughout the engineering plant
Sailors in Boilerman, Machinist’s Mate, Engineman, Electrician’s Mate, Hull Maintenance Technician, Damage Controlman, and other engineering ratings worked routinely in spaces where these materials were installed, maintained, ripped out, and replaced.
VA Benefits for Impervious Veterans
The Department of Veterans Affairs recognizes mesothelioma, asbestos-related lung cancer, asbestosis, and pleural disease as conditions that may be service-connected for Navy veterans with documented asbestos exposure. The Impervious equipment manifest is direct documentary evidence of the asbestos-containing materials her crew worked around throughout her service life.
Parallel claims against the asbestos bankruptcy trust funds established by the manufacturers of these products are also available, and do not reduce VA compensation.
Equipment manifest derived from public-record BUSHIPS documentation specific to USS Impervious (MSO-449). Manufacturer attribution links to documented asbestos-product histories on AsbestosIndex.com where available. Editorial review applied per site standards.
AsbestosIndex™Product & Manufacturer Reference
The asbestos-containing products documented on U.S. Navy vessels and at shipyards are catalogued by manufacturer on AsbestosIndex. These records cross-reference which companies supplied which materials and to which facilities.
Documented Asbestos-Exposure Environments — U.S. Navy Service
Public-domain U.S. Navy photographs illustrating the engineering spaces, ratings, and yard environments where asbestos materials were routinely encountered during normal duty.
All images are public domain (U.S. Government works). Specific photographs depict generic Navy engineering and yard environments — not the named vessel above. Asbestos materials shown or implied include pipe lagging, boiler insulation, steam-line covering, and gasket / packing materials standard on U.S. Navy vessels through the early 1980s.
Impervious MSO-449 — Frequently Asked Questions
Are Impervious MSO-449 veterans covered by Navy asbestos litigation records?
Yes. Impervious MSO-449 is documented in the public U.S. Navy asbestos litigation record. U.S. Navy vessels of her service era were built to BUSHIPS specifications that required asbestos insulation throughout engineering spaces, on steam lines, around boilers and turbines, and in gasket and packing materials.
Which shipboard components on Impervious MSO-449 contained asbestos?
Asbestos-containing materials documented aboard U.S. Navy vessels of Impervious MSO-449's era include: boiler insulation and lagging, steam-line pipe insulation, turbine and reduction-gear casings, valve packing, gaskets, brake and clutch friction materials, electrical wire insulation, overhead pipe coverings in berthing and mess spaces, and Navy-issue boiler cement and refractory in fireboxes.
What ratings were exposed to asbestos serving on Impervious MSO-449?
Navy ratings with the highest documented asbestos exposure include Machinist's Mate (MM), Boiler Technician (BT), Hull Maintenance Technician (HT), Engineman (EN), Electrician's Mate (EM), Interior Communications Electrician (IC), Damage Controlman (DC), and Pipefitter / Shipfitter. Officers in engineering departments also encountered asbestos in normal duty. Shipyard workers performing overhaul, repair, or refit work had concentrated exposure during yard periods.
What equipment manufacturers are documented on Impervious MSO-449?
Documented equipment manufacturers aboard Impervious MSO-449 include: Carrier Co., Delco, E B Badger & Sons Co., Gardner Denver Co., Gould, Hallet Mfg-Westinghouse, Packard Motor. These manufacturers supplied boilers, turbines, pumps, valves, electrical equipment, and insulation systems through BUSHIPS contracts during the asbestos era.
Do Impervious MSO-449 veterans qualify for VA disability for mesothelioma?
Potentially. VA evaluates asbestos-related disability claims individually. Impervious MSO-449 veterans generally need medical records showing the current disease, service records supporting in-service asbestos exposure, and a doctor's statement connecting the two. Veterans may file at VA.gov, call 1-800-827-1000, or seek free help from an accredited Veterans Service Organization such as DAV, VFW, or the American Legion.
Disclaimer: The information in this article is for general educational purposes only and does not constitute medical or legal advice. No attorney-client relationship is created by reading this site. References to ships, shipyards, companies, products, and asbestos-containing materials are drawn from public VA records, NARA archives, EPA/OSHA databases, and public litigation records. All references reflect what has been documented or alleged in publicly filed records. Consult a licensed physician for medical guidance and a qualified attorney for legal advice regarding your specific situation.
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Navy veterans and civilian shipyard workers diagnosed with mesothelioma, asbestosis, or asbestos-related lung cancer may have grounds for a civil claim against the asbestos product manufacturers whose materials were installed aboard. O'Brien Law Firm represents veterans and their families in the civil track at no upfront cost — separate from any VA disability benefits you may be eligible for.
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Maritime statute of limitations: 3 years from diagnosis (46 U.S.C. § 30106)
Runs in parallel with VA benefits — civil recovery does not reduce VA disability compensation
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