USS Leader (AM-490)

Evidence

12 evidence entries recorded; each entry has a stable permalink (#ev-1 … #ev-12).

1. [1]DANFS, 'Leader' (MSO-490) - verbatim transcription at the losthistory.net/hazegray mirror (live history.navy.mil DANFS pages return 404 - standing link rot, same as BATCH-01/1334) [nhhc_danfs]

   Locator

   DANFS 'Leader' entry, MSO-490 section - specifications block + service narrative + transcriber's note (losthistory.net/hazegray/danfs/mine/mso490.htm)

   Finding type

   vessel_history

   Finding

   Official DANFS record for this hull: '(MSO-490: dp. 620 lt.; 172; b. 36'; dr. dr. 10'; 15 k.; cpl. 74; cl. Aggressive). Leader (AM-490) was laid down by J. M. Martinac Shipbuilding Corp., Tacoma, Wash., 22 September 1953; launched 15 September 1954; sponsored by Mrs. Norman Wordlund; reclassified MSO-490 7 February 1955, and commissioned 16 November 1955, Lt. Comdr. Harvey Toponce in command.' Service narrative: shakedown, joined Mine Squadron 9 at Long Beach 21 December 1955; first WestPac cruise 1 October 1956 - 12 April 1957 (Yokosuka 30 October, five months of 7th Fleet mine warfare exercises); six WestPac cruises alternating with west-coast mine warfare/mine countermeasures exercises 1959-1968; first warship to visit Phnom Penh via 180-mile Mekong transit 27 August 1961, and directed South Vietnamese units in minesweep training on that cruise; special minesweeping operations off South Vietnam June-August 1965, returning to Long Beach 14 December; extensive overhaul 9 May - 30 September 1966; WestPac deployment from 6 January 1967 (Market Time operations), returned 18 November; departed Long Beach 12 August 1968, operating off Vietnam into 1969. Transcriber's note: 'Decommissioned 12 December 1991 and struck from the Navy Register 18 March 1992, Leader was sold 15 April 1994 and scrapped.'

   Verification

   verified

   Role

   supporting

   Documentation level

   ship_specific

   Accessed

   2026-09-22

   Study period

   1953-1994

   Population

   Martinac construction trades (1953-55); commissioned crew (design complement 74-78), 1955-1970 and 1972-1991; overhaul-yard workforces

   Limitations

   DANFS documents identity, builder, dates, and service narrative - not materials or asbestos content. Its spec block (620 lt, 36' beam, 10' draft, 15 kts, cpl 74) conflicts with NavSource's (775 t, 35', 12', 14 kts, 78) and Colton's (780d) - flagged in ev-10. The 1966 overhaul yard is not named. The DANFS narrative ends in 1969; the 1991-94 disposal detail is the transcriber's note, not DANFS text. Mirror transcription cited because the live NHHC page returns 404.

   Atlas source

   true

   Evidence ID

   ev-uss-leader-am490-01

2. [2]NavSource Online: Mine Warfare Vessel Photo Archive - Leader (MSO-490) ex-AM-490, file 11/02490; plus NavSource Mine Warfare index 11/02idx (class construction description) [other_primary]

   Locator

   NavSource 11/02490 - chronology block, spec block, propulsion line, CO list (29 COs, LCDR Toponce through LCDR Lehr), photo credits with NARA/DoD identifiers; index 11/02idx MSO-class header

   Finding type

   vessel_history

   Finding

   NavSource per-hull record: 'Aggressive Class Minesweeper'; laid down 22 September 1953 as AM-490 by the 'J. L. Martinac Shipbuilding Corp.' (typo for J. M.), Tacoma, WA; launched 15 September 1954; 'Reclassified as an Ocean Minesweeper, MSO-490, 7 February 1955'; commissioned USS Leader (MSO-490) 16 November 1955; decommissioned 30 November 1970 at Naval Station Long Beach, CA and moved to Harbor Boat Yard, Terminal Island, CA for a modernization overhaul; 'Recommissioned "Special" 11 February 1972 at Long Beach'; recommissioned 6 March 1972; decommissioned 12 December 1991 and laid up at Naval Inactive Ship Maintenance Facility, Portsmouth, VA; struck from the Naval Register 18 March 1992; 'Sold for scrap 18 August 1994 by Defense Reutilization and Marketing Service to NR Aquilinity of New York, NY for $28,880. Broken up at Wilmington, NC.' Spec block: 775 t; 172'; 35' beam; 12' draft; 14 kts; complement 78; armament as built one single 40mm mount + two .50-cal., final configuration bow gun replaced by one twin 20mm mount; propulsion four Packard ID1700 diesels replaced by four 'Waukasha Motors Co.' (Waukesha) diesels, two shafts, two controllable-pitch propellers. Photo captions document: in port with Engage (MSO-433) and Dominant (MSO-431) during the 1980 Mariel Boatlift (U.S. Navy photo, Wright Langley Collection/Florida Keys Public Libraries); Naval Station Charleston 1 October 1984 (DN-ST-88-02046); aboard heavy-lift ship Super Servant 3 at Bahrain 5 October 1990 for Desert Shield offload (DN-SC-91-02583); departing a Saudi port on a Desert Shield minesweeping mission (DoD photo, NAID 6479770); underway on post-cease-fire mine-clearing operations 1991 (DoD photo, NAID 6484644); outboard of Avenger (MCM-1) c. 1991. CO list documents 29 commanding officers 1955-1991 including rotating Blue/Gold crews in 1988-1991. NavSource class index: the 1950s MSO program comprised 'Agile/Aggressive' hulls 421-507, Acme 508-518, Ability 519-522 - 'built primarily of wood, with bronze and stainless (non-magnetic) steel fittings to minimize their magnetic signature,' UQS-1 mine-locating sonar (later SQQ-14).

   Verification

   partial

   Role

   supporting

   Documentation level

   ship_specific

   Accessed

   2026-09-22

   Study period

   1953-1994

   Population

   Martinac trades (1953-55); Harbor Boat Yard modernization workforce (1970-72); crew 1955-1991

   Limitations

   Specialist secondary compilation - detailed but non-official. Its spec block conflicts with DANFS's on displacement, beam, draft, speed, and complement - flagged in ev-10. Its 'J. L. Martinac' reads as a typo for J. M. Martinac (DANFS, NVR, Colton, Combat Fleets all read J. M.). Its 'twin 20mm mount' final armament conflicts with Combat Fleets's listing of MSO-490 among post-1970-modernized ships with all guns removed - flagged in ev-10. Contains no asbestos information; supports no asbestos claim. The class-construction description (wood hull, non-magnetic fittings) is class-level, not a hull material record.

   Atlas source

   true

   Evidence ID

   ev-uss-leader-am490-02

3. [3]Shipbuilding History (Tim Colton compilation), 'Martinac Shipbuilding, Tacoma WA' yard table - MSO 490 Leader row + sister-MSO block + yard history header [other_primary]

   Locator

   martinac.htm - MSO 490 Leader row; sisters MSO 489/491; yard-history header

   Finding type

   vessel_history

   Finding

   Yard-table row for this hull: 'MSO 490 | Leader | U.S. Navy | Minesweeper | 780d | 172 | 16-Nov-55 | Scrapped 1994.' The Martinac table carries her near-sisters in the same block: MSO 489 Gallant (780d, 172 ft, delivered 14-Sep-55, to Taiwan 1995 as Yung Der M 1308) and MSO 491 Persistent (780d, 172 ft, delivered 3-Feb-56, to Spain 1971). Yard history header: Joseph M. Martinac founded the J. M. Martinac Shipbuilding Corp. in 1924; built commercial and governmental boats; yard on the east side of the Thea Foss Waterway at the foot of East 15th Street; closed 2014, property sold for development.

   Verification

   verified

   Role

   supporting

   Documentation level

   ship_specific

   Accessed

   2026-09-22

   Study period

   1953-1955

   Population

   J. M. Martinac workforce (Tacoma, WA, 1953-55)

   Limitations

   Compiler's yard table, secondary - corroborates builder, type, delivery/commissioning (16-Nov-55), and scrapping year (1994). Its '780d' displacement conflicts with DANFS's 620 lt and NavSource's 775 t - flagged in ev-10. Contains no asbestos information; supports no asbestos claim.

   Atlas source

   true

   Evidence ID

   ev-uss-leader-am490-03

4. [4]Naval Vessel Register, 'LEADER (MSO 490) (ex-AM 490)' detail page - NAVSEA/NAVSHIPSO official inventory record (live nvr.navy.mil detail URLs redirect to a generic index; Wayback capture 2016-07-26 of record last updated 2000-07-03) [other_primary]

   Locator

   Wayback 2016-07-26 capture of nvr.navy.mil/NVRSHIPS/DETAILS/MSO490.HTM - data table (UIC, class, status, builder, award/keel/launch/delivery/commission/decommission/stricken dates, custodian)

   Finding type

   vessel_history

   Finding

   Official NVR record for this hull: type 'MINESWEEPER,OCEAN'; UIC 08148; class 'MSO 422' (the Aggressive-class group); status 'Disposed of, by Navy Sale'; date status changed 04/15/1994; builder 'J M MARTINAC SB CORP'; award date 12/29/1952; keel 09/22/1953; launch 09/15/1954; delivery date 11/03/1955; commission date 11/16/1955; 'Decommission Date: 03/18/1992'; stricken date 03/18/1992; age since delivery at disposal 38.4 years; years commission to decommission 36.3; custodian 'SCHOOLS, ORGANIZATIONS AND PRIVATE ENTERPRISES'; last updated 07/03/2000.

   Verification

   verified

   Role

   supporting

   Documentation level

   ship_specific

   Accessed

   2026-09-22

   Study period

   1952-1994 (record last updated 2000)

   Population

   NISMF Portsmouth layup staff (1991-94); DRMS/scrapping workforce (1994)

   Limitations

   Official inventory record, but a disposal-tracking record - it carries dates and custody events, not materials or asbestos content, and its dimension/propulsion fields are blank for this hull. Its 'Decommission Date: 03/18/1992' conflates the stricken date - NavSource/NavalCoverMuseum/Wikipedia carry the actual out-of-commission date as 12 December 1991 (flagged in ev-10). Its 04/15/1994 'Navy Sale' status-change date and NavSource's 18 August 1994 DRMS sale contract are carried as a custody sequence, not merged (ev-10). Live NVR detail pages redirect to a generic index (site reorganization); the 2016-07-26 Wayback capture is cited.

   Atlas source

   true

   Evidence ID

   ev-uss-leader-am490-04

5. [5]Combat Fleets of the World (Wertheim naval almanac transcript, jwilliamcupp.name mirror) - MSO 490 Leader line, modernization table, SCB-502 program description, and class table [other_primary]

   Locator

   CombFlt.htm - MSO 490 row; modernization table (488/490 Harbor Boat Building rows); SCB-502 program paragraphs; Agile/Aggressive class table

   Finding type

   vessel_history

   Finding

   Almanac line for this hull: 'MSO 490 LEADER J. M. Martinac 22SEP53 15SEP54 16NOV55 stricken before 92.' Modernization table row: '490 Harbor Boat Building 30JUN70 30NOV70 30NOV70 11FEB72' - SCB-502 modernization at Harbor Boat Building (Terminal Island) beginning 30 June 1970, decommissioned 30 November 1970, returned to commission 11 February 1972 (consistent with NavSource's 'Special' 11 Feb 1972 / full 6 Mar 1972). Program description: the FY1968 SCB-502 modernization replaced Packard diesels with four Waukesha Motors Co. diesels in some ships, added two or three diesel-electric generators for the minesweeping gear, fitted the GE AN/SQQ-14 ('Squeaky 14') mine-detection sonar on a massive external forecastle hoist in place of the 40mm gun, extended the bridge structure, retrofitted chill-water air conditioning, and set modernized-ship complement at 6 officers + 70 enlisted; 'Some ships modernized after 1970 had all guns removed (MSO 437,439,490).' Leader appears in the 'Ships Fully Modernized (SCB# 502)' list (433, 437, 438, 441, 442, 443, 445, 446, 448, 449, 456, 488, 490). Class table: 'AGILE Class, 421' single hull + 'AGGRESSIVE Class, 422-427, 432-449, 455-474, 488-496' - placing hull 490 in the Aggressive class; 172 ft, 35 ft beam, 775 tons, 10 ft draft, 14 knots, Packard machinery.

   Verification

   partial

   Role

   supporting

   Documentation level

   ship_specific

   Accessed

   2026-09-22

   Study period

   1953-1992

   Population

   Harbor Boat Building modernization workforce (Terminal Island, 1970-72)

   Limitations

   Secondary almanac transcript - corroborates the build/commission spine, the builder, the SCB-502 modernization event at Harbor Boat Building, and the disposal-era strike ('stricken before 92' vs the precise 18 Mar 1992 elsewhere - the almanac is approximate). Its all-guns-removed listing for MSO-490 conflicts with NavSource's 'twin 20mm mount' final configuration - flagged in ev-10. Contains no asbestos information; supports no asbestos claim. The SCB-502 scope (engine swap, generators, sonar, habitability refit) documents disturbance events but says nothing about material content.

   Atlas source

   true

   Evidence ID

   ev-uss-leader-am490-05

6. [6]U.S. Department of Defense, 'United States Navy in Desert Shield/Desert Storm' (GulfLink declassified history archive), mine countermeasures narrative [other_primary]

   Locator

   gulflink.health.mil/histories/db/navy/usnavy_056.html (narrative p.42); NavSource 11/02490 photo captions; en.wikipedia.org/wiki/USS_Leader_(MSO-490) Desert Storm section

   Finding type

   vessel_history

   Finding

   Official DoD history names this hull in the Gulf mine-countermeasures force: 'The minesweepers USS ADROIT (MSO 509), USS IMPERVIOUS (MSO 449), and USS LEADER (MSO 490) along with the newly commissioned mine countermeasures ship USS AVENGER (MCM 1) arrived in the Gulf aboard the heavy-lift ship Super Servant [III].' The U.S. Mine Countermeasures Group cleared a lane 60 miles east of the Kuwaiti coastline and pushed 24 miles to 'Point FOXTROT,' the 10-mile by 3.5-mile battleship gunfire-support area south of Faylaka Island. On 18 February 1991, when USS TRIPOLI (LPH 10) and USS PRINCETON (CG 59) struck Iraqi mines within three hours of each other, 'IMPERVIOUS, LEADER and AVENGER searched for additional mines in the area' while ADROIT led the salvage tug USS BEAUFORT (ATS 2) toward Princeton. NavSource photo captions independently document Leader aboard Super Servant 3 at Bahrain 5 October 1990 (DN-SC-91-02583) and departing a Saudi port on a Desert Shield minesweeping mission (NAID 6479770); Wikipedia's Desert Storm section (incorporating NHHC public-domain material) records the load aboard Super Servant 3 at Norfolk 19 August 1990 alongside Impervious, Adroit, and Avenger.

   Verification

   verified

   Role

   supporting

   Documentation level

   ship_specific

   Accessed

   2026-09-22

   Study period

   1990-08-19 to 1991

   Population

   Leader crew (1990-91 Gulf deployment, rotating Blue/Gold crews per NavSource CO list)

   Limitations

   Operational history only - documents Gulf deployment and mine-clearing operations, not materials or asbestos content. Establishes that this hull's crew operated in a combat MCM environment 1990-91; it does not establish exposure to anything. The OCR-scanned GulfLink pages contain typographical noise ('TRIPOU', 'ADROfl') - quoted forms verified against context.

   Atlas source

   true

   Evidence ID

   ev-uss-leader-am490-06

7. [7]Consolidated era/design inference - documented construction and machinery (NavSource class index 'built primarily of wood, with bronze and stainless (non-magnetic) steel fittings'; NavSource spec block: four Packard ID1700 diesels replaced by four Waukesha diesels, two CPPs - no boilers or steam) + documented builder and construction era (DANFS; NVR; Colton) + documented SCB-502 modernization scope (Combat Fleets: engine swap, added generators, SQQ-14 sonar, chill-water AC habitability retrofit) [other_primary]

   Locator

   NavSource 11/02idx class header; NavSource 11/02490 propulsion line; DANFS 'cl. Aggressive' + service narrative; NVR record; Colton martinac.htm; Combat Fleets SCB-502 paragraphs

   Finding type

   asbestos_application

   Finding

   Era/design inference: this hull is a 1953-55-built wooden-hulled non-magnetic ocean minesweeper with a diesel direct-drive plant (four Packard ID1700s, replaced 1970-72 by four Waukesha diesels; two controllable-pitch propellers) - no steel hull to insulate, no boilers, no steam distribution. Its insulation load was materially lighter than a steam combatant's and lighter even than a steel-hulled diesel minesweeper's. Era-typical asbestos applications for a 1950s naval vessel of this type: exhaust-system and muffler lagging on the diesel plant; machinery gaskets and packing; electrical-cable insulation; accommodation and galley joiner materials; deck coverings/floor tile; winch and windlass brake linings. Exposure-relevant populations if any material was present: Martinac construction trades (Tacoma, 1953-55); the commissioned crew (~74-78) across 1955-1970 and 1972-1991, including Vietnam and Gulf deployments; yard workers during the undocumented-yard 1966 overhaul and the documented Harbor Boat Building SCB-502 modernization (1970-72 - engine swap, generator additions, sonar install, habitability refit is the largest disturbance episode in the record); and the 1994 Wilmington, NC scrapping workforce.

   Verification

   inferred

   Role

   supporting

   Documentation level

   class_or_era

   Accessed

   2026-09-22

   Study period

   1953-1994

   Population

   Martinac trades (1953-55); crew 1955-1991; Harbor Boat Building workforce (1970-72); scrapping workforce (1994)

   Limitations

   Inference from documented design, machinery type, and construction era - NOT a hull materials record. No survey, specification, or material schedule naming AM-490/MSO-490 was located; establishes no asbestos content, quantity, location, condition, individual exposure, or causation. The wooden hull and diesel (non-steam) plant make even era-level inference weaker than for steel or steam vessels of the same era. The SCB-502 modernization's asbestos scope (what insulation was disturbed or replaced) is undocumented.

   Atlas source

   true

   Evidence ID

   ev-uss-leader-am490-07

8. [8]GAO HRD-80-2, 'Navy Efforts To Protect Workers From Asbestos Exposure' (1979-80); and T.J. Bigley (Navy) letter to GAO, 5 Jan 1979, as quoted in 'The Asbestos Health Hazards Compensation Act,' Journal of Legislation (Notre Dame) 10(1) [gao]

   Locator

   GAO HRD-80-2 product/PDF (gao.gov/assets/hrd-80-2.pdf); Notre Dame J. Legislation 10(1), 'The Asbestos Health Hazards Compensation Act' (scholarship.law.nd.edu/jleg/vol10/iss1/3) quoting Bigley letter of 5 Jan 1979

   Finding type

   gov_survey

   Finding

   Program-level documentation of the asbestos window this hull's construction and first commission fall inside: GAO HRD-80-2 records that the Navy's product specifications for thermal insulation were changed in 1973 to specify asbestos-free materials, but asbestos materials already purchased were still installed - 'some ships were delivered with asbestos insulation as late as May 1978'; the Navy's elimination policy issued October 1975. A Navy letter to GAO dated 5 January 1979 (T.J. Bigley to Robert F. Hughes, quoted in the Notre Dame Journal of Legislation) states: 'all ships presently in service contain some quantity of asbestos.' Leader was built 1953-55, in commission 1955-1970 and 1972-1991 - entirely within the pre-1973 as-built asbestos era and the 1979 all-ships statement's window, and still in service when the statement was written.

   Verification

   verified

   Role

   context

   Documentation level

   class_or_era

   Accessed

   2026-09-22

   Study period

   1973-1979 policy window documented; hull era 1953-1991

   Population

   Navy personnel and shipyard workers, service-wide (era context)

   Limitations

   Program/era-level documentation; neither source names this vessel, class, or builder. GAO's fieldwork concerned shipyard workers (Long Beach, Norfolk). The 'all ships ... contain some quantity of asbestos' statement is quoted from a primary letter via a law-review source - the letter itself was not retrieved. gao.gov returns HTTP 403 to automated fetch (standing, same as BATCH-01/1334); the PDF text was confirmed via search-snippet extraction, not full-text pull. Establishes nothing about this hull's materials, condition, or any individual exposure - and for a wooden-hulled diesel ship the proposition applies with materially reduced scope.

   Atlas source

   true

   Evidence ID

   ev-uss-leader-am490-08

9. [9]Batch-1390 search ledger (this record): DANFS via hazegray/losthistory mirror; NavSource 11/02490 + 11/02idx class index; Shipbuilding History Martinac yard table; NVR detail page via Wayback 2016-07-26 capture; Combat Fleets transcript; DoD GulfLink Desert Storm history; NavalCoverMuseum wiki; CourtListener API v4 (throttled) + site-scoped web search; NARA catalog [other_primary]

   Locator

   search_ledger rows sl-uss-leader-am490-01 through sl-uss-leader-am490-14

   Finding type

   historical_record

   Finding

   No qualifying ship-specific asbestos record located for USS Leader / AM-490 / MSO-490: no asbestos survey, abatement contract, hazmat disclosure, preservation record, court finding, or docketed asbestos case naming this hull was found in the public sources searched (see search_ledger). CourtListener's authenticated API returned HTTP 429 at session time (shared 2,800/day quota exhausted by prior batch work; reset ~6h) - per protocol no unauthenticated queries were run and the opinion/RECAP sweeps are logged as blocked rather than retried into a ban. Site-scoped web search of courtlistener.com and a general asbestos-litigation web search surfaced only unrelated Navy-asbestos filings - no vessel association. Non-authoritative marketing rosters (mesothelioma.com minesweepers jobsites table: 'USS Leader | AM-490 | Aggressive | 11/16/1955 | Scrapped, 1994'; mesotheliomahelp.org minesweeper list entry 'USS Leader'; navyshipexposure.com dedicated MSO-490 page asserting generic class-pattern equipment claims) carry the name in generic ship tables or generated content - excluded per source rules; they carry no hull-specific evidence.

   Verification

   verified

   Role

   negative_finding

   Documentation level

   ship_specific

   Accessed

   2026-09-22

   Study period

   2026-09-22

   Limitations

   Absence of a located public record does not prove absence of asbestos aboard - a 1953-55 naval vessel is era-consistent with asbestos-containing materials even accounting for its wooden hull and lighter diesel insulation load. The hull was scrapped in the U.S. in 1994, so no present-day survey pathway exists. The CourtListener sweep is incomplete (quota) - residual risk that a differently-phrased hull reference exists is logged as a gap. Does not establish presence or absence; does not establish or defeat any exposure claim or legal eligibility.

   Atlas source

   true

   Evidence ID

   ev-uss-leader-am490-09

10. [10]Source-discrepancy resolution - DANFS (hazegray mirror) vs NavSource 11/02490 vs NVR detail record (Wayback) vs Colton Martinac yard table vs Combat Fleets transcript vs NavalCoverMuseum vs Wikipedia infobox [other_primary]

    Locator

    losthistory.net/hazegray/danfs/mine/mso490.htm; navsource.net/archives/11/02490.htm + 11/02idx.htm; Wayback NVR MSO490 detail; shipbuildinghistory.com/shipyards/small/martinac.htm; jwilliamcupp.name/Story/CombFlt.htm; navalcovermuseum.org/wiki/LEADER_MSO_490; en.wikipedia.org/wiki/USS_Leader_(MSO-490)

    Finding type

    historical_record

    Finding

    Source discrepancies logged, not silently merged: (a) Decommission date - NavSource/NavalCoverMuseum/Wikipedia/DANFS transcriber note '12 December 1991' vs NVR detail 'Decommission Date: 03/18/1992' (= the stricken date) - the 12 Dec 1991 out-of-commission date carried, NVR's field treated as conflating strike; both recorded. (b) Disposal dates - NVR 'Disposed of, by Navy Sale' status changed 04/15/1994 and DANFS transcriber 'sold 15 April 1994 and scrapped' vs NavSource/NavalCoverMuseum 'Sold for scrap 18 August 1994 by DRMS to NR Aquilinity of New York, NY for $28,880' - reconciled as Navy disposal authorization April 1994 followed by DRMS scrap-sale contract August 1994; flagged not merged. (c) Displacement - DANFS 620 lt vs NavSource/Wikipedia 775 t vs Colton 780d - DANFS light-displacement figure carried in the spec summary, full-load ~775-780 t noted. (d) Beam - DANFS/Wikipedia 36' vs NavSource/Combat Fleets class table 35' - flagged. (e) Draft - DANFS/Wikipedia 10' vs NavSource 12' - flagged. (f) Speed - DANFS/Wikipedia 15 kts vs NavSource/Combat Fleets 14 kts - flagged. (g) Complement - DANFS/Wikipedia 74 vs NavSource 78 vs Combat Fleets class table '5 and 70' (75) and modernized-ship '6 officers + 70 enlisted' (76) - flagged. (h) Final armament - NavSource 'bow gun removed and replaced with one twin 20mm mount' vs Combat Fleets listing MSO-490 among post-1970-modernized ships with 'all guns removed' - flagged, unresolved. (i) Builder name - NavSource 'J. L. Martinac' vs DANFS/NVR/Colton/Combat Fleets 'J. M. Martinac' - NavSource treated as typographical error. (j) Class label - DANFS 'cl. Aggressive', NVR 'MSO 422', NavSource 'Aggressive Class Minesweeper', Combat Fleets Aggressive block 488-496 vs Wikipedia 'Agile class' - Aggressive class carried; 'Agile' is the loose series grouping (NavSource index: 'Agile/Aggressive, hull numbers 421 to 507'). (k) Name numbering - DANFS treats PYc-42 (ex-Curlew, 1942-1945) as the first Leader; MSO-490 is the second of the name.

    Verification

    partial

    Role

    correction

    Documentation level

    ship_specific

    Accessed

    2026-09-22

    Study period

    1953-1994

    Limitations

    Resolves publication-level discrepancies among the official DANFS text, the official NVR record, and secondary compilations, adopting the better-supported values and flagging the rest. None of the sources bears on asbestos; the disposal chain is reconciled at the level of custody events (strike -> NVR 'Navy Sale' status -> DRMS scrap contract -> breakup at Wilmington NC) because the component sources emphasize different milestones.

    Atlas source

    true

    Evidence ID

    ev-uss-leader-am490-10

11. [11]Wineland v. Air & Liquid Sys. Corp., 539 F. Supp. 3d 1149 (W.D. Wash. 2021), Cause No. C19-0793RSL (Judge Lasnik) - order granting Crane Co.'s motion for summary judgment (Dkt. #304); companion orders grant other defendants' MSJs (e.g., Puget Sound Commerce Center/Todd Shipyards Dkt. #302, 523 F. Supp. 3d 1245; Carrier Dkt. #427) [court_record]

    Locator

    539 F. Supp. 3d 1149 (W.D. Wash. 2021); docket 2:19-cv-00793-RSL (W.D. Wash.); companion order 523 F. Supp. 3d 1245; order PDF mirrors brownsims.com

    Finding type

    litigation_documented

    Finding

    Class-adjacent asbestos litigation exists for this vessel type: plaintiffs alleged decedent John Dale Wineland was exposed to asbestos-containing products while working engine rooms aboard Navy ships 1963-1984, including Agile/Aggressive-series ocean minesweepers USS Dynamic (MSO-432), USS Pledge (MSO-492), USS Loyalty (MSO-457), and USS Esteem (MSO-438) - sisters of this hull in the same wooden-hulled, diesel-engined MSO design family (plus the LST USS Tuscaloosa). The published orders record machinery-space work on 'diesel engines, pumps, air compressors, and valves' and litigation-stage product-identification evidence. Disposition per litigation-stage discipline: the located rulings are summary-judgment-stage defense wins (Crane Co. MSJ granted, 539 F. Supp. 3d 1149; companion MSJs granted) - merits-level negatives for that plaintiff, not exposure findings; the vessel/product allegations are pleadings and motion-stage record assertions, not adjudicated facts. No appellate disposition was located.

    Verification

    verified

    Role

    context

    Documentation level

    class_or_era

    Accessed

    2026-09-22

    Study period

    2019-2021 litigation; exposure period alleged 1963-1984

    Population

    MSO engine-room sailors (class context), 1963-1980

    Limitations

    Context only - the cited case does not name or involve USS Leader/AM-490/MSO-490, and its sister-ship allegations never reached a merits finding on exposure. It establishes only that asbestos claims were litigated at the pleading/SJ stage for the same MSO type and diesel machinery spaces. Does not establish or defeat any exposure claim or legal eligibility for this hull. CourtListener API was quota-blocked at session time; the reporter citation and docket are verified via vLex metadata and the order PDFs mirrored at brownsims.com (defense firm) - a CourtListener opinion URL was not resolved.

    Atlas source

    true

    Evidence ID

    ev-uss-leader-am490-11

12. [12]Archival leads - NARA RG 24 deck logs for this hull's two commission periods (Nov 1955-Nov 1970; Feb 1972-Dec 1991); muster rolls; NARA-cataloged DoD still imagery credited on NavSource (DN-ST-88-02046 Charleston 1984; DN-SC-91-02583 Super Servant 3 at Bahrain 5 Oct 1990; NAID 6479770 Desert Shield minesweeping mission; NAID 6484644 post-cease-fire mine clearing 1991); NARA RG 19 Bureau of Ships records / General Information Books and the Navy contract file for the Martinac MSO block (AM 489-491 group); the SCB-502 modernization work package; the Harbor Boat Building/Terminal Island job file (1970-72); the 1966 overhaul yard file (yard unidentified); and the DRMS disposal file for the August 1994 NR Aquilinity sale [other_primary]

    Locator

    archives.gov RG 19/24 group guides; NavSource 11/02490 photo credits (DN-ST-88-02046, DN-SC-91-02583, NAID 6479770, NAID 6484644); NVR award/delivery fields

    Finding type

    historical_record

    Finding

    Archival leads (not retrieved - require research-room or reproduction order; no spend authorized; NARA catalog returns only its JS application shell to automated fetch): (a) NARA RG 24 deck logs, Nov 1955-Nov 1970 and Feb 1972-Dec 1991; (b) muster rolls for the commission periods; (c) NARA/DoD still imagery already cataloged in NavSource credits - including the 1990-91 Gulf deployment series (DN-SC-91-02583; NAID 6479770; NAID 6484644) and DN-ST-88-02046 (Charleston 1984); (d) NARA RG 19 BuShips records and the Navy contract file for the Martinac MSO block (award 29 Dec 1952 per NVR; sisters AM 489/491) - the plausible home of hull-level material schedules for the Aggressive design; (e) the SCB-502 modernization work package and Harbor Boat Building/Terminal Island job file (1970-72) - the documented machinery/habitability rip-out whose material scope is undocumented; (f) the 1966 overhaul file once the yard is identified; (g) the DRMS disposal file documenting the 1994 NR Aquilinity sale and Wilmington breakup.

    Verification

    unverified

    Role

    archival_lead

    Documentation level

    context_only

    Accessed

    2026-09-22

    Study period

    1953-1994 records

    Limitations

    Record-group mapping only - no box-level retrieval performed; existence of asbestos-specific documents for MSO-490 is unknown until surveyed in person. Deck logs, muster rolls, and contract files are personnel/operations records, not materials documentation; the BuShips design file and SCB-502 work package are the best candidates for a material schedule. Nothing in this row is an asbestos finding.

    Atlas source

    true

    Evidence ID

    ev-uss-leader-am490-12