Evidence
10 evidence entries recorded; each entry has a stable permalink (#ev-1 … #ev-10).
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[1]DANFS, Leader (MSO-490) - construction, sponsor, reclassification, commissioning, Mine Squadron 9 service, WestPac cruises, Vietnam operations (verbatim transcription; live NHHC page returned 404; original hazegray.org DNS-dead) [nhhc_danfs]
- Locator
- DANFS service narrative, spec block, and transcriber's note
- Finding type
- vessel_history
- Finding
- Documented for this hull: laid down by J. M. Martinac Shipbuilding Corp., Tacoma, Wash., 22 September 1953 as AM-490; launched 15 September 1954, sponsored by Mrs. Norman Wordlund; reclassified MSO-490 7 February 1955; commissioned 16 November 1955, Lt. Comdr. Harvey Toponce in command. Joined Mine Squadron 9 at Long Beach 21 December 1955; first WestPac cruise departed 1 October 1956 (Yokosuka 30 October), returned 12 April 1957; six WestPac cruises 1959-1968 alternating with west coast mine warfare exercises. First warship to visit Phnom Penh - completed the 180-mile Mekong River transit 27 August (1961 cruise); directed South Vietnamese minesweep training on the same cruise. Special minesweeping operations off South Vietnam June-August 1965; returned Long Beach 14 December. Extensive overhaul 9 May - 30 September 1966. Departed for WestPac 6 January 1967, Market Time operations most of the tour, returned 18 November 1967; departed 12 August 1968, operating off Vietnam into 1969. Spec block: dp. 620 lt.; l. 172'; b. 36'; dr. 10'; s. 15 k.; cpl. 74; cl. Aggressive.
- Verification
- verified
- Role
- context
- Documentation level
- ship_specific
- Accessed
- 2026-10-03
- Study period
- 1953-1969 (entry coverage)
- Population
- Martinac construction trades (1953-55); crew (1955-forward); Long Beach homeport population
- Limitations
- Ship-specific history only; no asbestos or material content. DANFS narrative coverage ends in 1969 - post-1969 milestones come from other rows. Live NHHC DANFS page returned 404 on 2026-10-03 for all candidate URLs (leader.html, leader-ii.html, leader-mso-490.html); verbatim transcription via losthistory.net/hazegray mirror used (hazegray.org itself DNS-dead). Transcriber's note adds decommissioning/strike/sale dates that conflict with NavSource on the 1994 sale date (see gaps).
- Atlas source
- true
- Evidence ID
- ev-uss-leader-mso490-01
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[2]NavSource Online: Mine Warfare Vessel Photo Archive, Leader (MSO-490) ex-AM-490 - designation timeline, specifications, post-1969 milestones, disposal, commanding-officer list, DoD/NARA-captioned photography [other_primary]
- Locator
- NavSource 11/02490.htm header block, specifications block, photo captions (incl. NARA-identified DoD photos), commanding-officer table; Super Servant 4 return captions on companion page 11/02449.htm (Impervious)
- Finding type
- vessel_history
- Finding
- NavSource timeline for this hull: laid down 22 September 1953 as AM-490 by the 'J. L. Martinac' Shipbuilding Corp., Tacoma (NavSource spelling; 'J. M. Martinac' per DANFS and Washington State records - see ev-08); launched 15 September 1954; reclassified ocean minesweeper MSO-490 7 February 1955; commissioned 16 November 1955; decommissioned 30 November 1970 at Naval Station Long Beach 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. Specifications: 775 t., 172', beam 35', draft 12', 14 kts., complement 78; propulsion 'Four Packard ID1700 diesel engines, replaced by four Waukesha Motors Co. diesel engines, two shafts, two controllable pitch propellers.' Call sign NYRD. Photographic record documents: Mariel Boatlift 1980 with Engage (MSO-433) and Dominant (MSO-431); Naval Station Charleston SC 1 October 1984; aboard heavy-lift Super Servant 3 for Desert Shield, offloaded Bahrain 5 October 1990; departing a Saudi port on a minesweeping mission (NAID 6479770); post-ceasefire mine-clearing (NAID 6484644); return to Norfolk, VA aboard Super Servant 4 on 14 November 1991 after a 14-month Persian Gulf deployment (captions on the companion Impervious (MSO-449) archive page 11/02449). Blue/gold crew rotation from January 1988 per commanding-officer list.
- Verification
- verified
- Role
- context
- Documentation level
- ship_specific
- Accessed
- 2026-10-03
- Study period
- 1953-1994
- Population
- Martinac construction trades (1953-55); crew (1955-70, 1972-91); Harbor Boat Yard trades (1970-72); NISMF Portsmouth inactivation population (1991-94); DRMS/scrapping trades Wilmington NC (1994)
- Limitations
- NavSource is a volunteer secondary compilation, not a primary registry - milestone dates generally track official records but spec figures conflict with DANFS (beam 35' vs 36', draft 12' vs 10', speed 14 vs 15 kts, complement 78 vs 74, displacement 775 vs 620 lt - see gaps). 'J. L. Martinac' and 'Waukasha' are spelling variants; 'NR Aquilinity' reads as a garbled buyer name. Contains no asbestos content; the 1970-72 modernization is documented as an event, its asbestos-handling scope is not.
- Atlas source
- true
- Evidence ID
- ev-uss-leader-mso490-02
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[3]Tamara Moser Melia, 'Damn the Torpedoes': A Short History of U.S. Naval Mine Countermeasures, 1777-1991 (Naval Historical Center, Department of the Navy, 1991) - official Navy history, HyperWar/ibiblio mirror [other_primary]
- Locator
- pp. 127, 132 (narrative and photo caption); index entry 'Leader (MSO-490): in Desert Storm, 127, 132'; 20-MSO force figure p. 131
- Finding type
- vessel_history
- Finding
- Official Naval Historical Center documentation naming this hull: in August 1990 'Avenger (MCM-1) and three MSOs, Adroit (MSO-509), Impervious (MSO-449), and Leader (MSO-490), were immediately sealifted to the Persian Gulf to provide MCM forces for Operation Desert Shield' (p. 127); photo caption p. 132: 'Leader and Avenger in the Persian Gulf, 1991. Desert Storm MCM operations required heroic efforts of MSO and MCM crews to clear gunfire support areas and to reopen shipping channels to Kuwait.' Context: operational U.S. MCM assets in 1989-90 were '20 Korean War-era MSOs in both the active and the reserve fleet' - this hull, commissioned 1955, was among them.
- Verification
- verified
- Role
- context
- Documentation level
- ship_specific
- Accessed
- 2026-10-03
- Study period
- 1990-1991
- Population
- Crew deployed to Persian Gulf (Aug 1990 - Nov 1991)
- Limitations
- Official ship-specific presence documentation for the Desert Shield/Storm deployment only; no asbestos content, no material content. The history names the hull in a fleet-level narrative - it does not document work performed aboard or conditions aboard this specific vessel.
- Atlas source
- true
- Evidence ID
- ev-uss-leader-mso490-03
-
[4]Tamara Moser Melia, 'Damn the Torpedoes' (NHC, 1991) - Aggressive-class design description and MSO modernization program account [other_primary]
- Locator
- pp. 82-83 (class design), pp. 95-96 (modernization program)
- Finding type
- vessel_history
- Finding
- Official class documentation: the Bureau of Ships' post-Wonsan ocean-minesweeper design (naval architect Philip L. Rhodes) produced 'the 172-foot Aggressive-class AMs, redesignated ocean minesweeper (MSO) in 1955' with 'enhanced electrical generating capacity for effective magnetic minesweeping'; 'the open-ocean sweeping MSOs were built with wooden hulls, few magnetic materials, and improved degaussing' and 'powered by special nonmagnetic Packard or General Motors diesel engines' with controllable-pitch propellers and UQS-1 minehunting sonar. Class history: MSOs suffered 'persistent mechanical problems and excessive wear on their wooden hulls,' and 'in the late 1960s an MSO modernization program was begun. Improvements included installation of new Waukesha nonmagnetic engines and the SQQ-14 minehunting and classifying sonar' - but the program 'reached its peak in 1969 with only thirteen of sixty-five ships completed' and failed on cost growth and technical deficiencies.
- Verification
- verified
- Role
- context
- Documentation level
- class_or_era
- Accessed
- 2026-10-03
- Study period
- 1949-1972 (design and modernization era)
- Population
- Aggressive-class construction trades and crews (class context)
- Limitations
- Class-level design and program documentation - does not name this hull. It contextualizes Leader's construction (nonmagnetic wooden-hull diesel ship) and her documented 1970-72 modernization overhaul (NavSource shows the Packard-to-Waukesha engine swap this program installed), but whether this hull received the full modernization package is not stated here. No asbestos content.
- Atlas source
- true
- Evidence ID
- ev-uss-leader-mso490-04
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[5]NavalCoverMuseum (Naval Cover Museum), LEADER MSO 490 - designation history and milestone corroboration, sponsor, cover/postmark record [museum_official]
- Locator
- Ship Name and Designation History table; NAMESAKE note; postmark examples (Long Beach 1959-03-23; Charleston SC 294 1975-09-17)
- Finding type
- vessel_history
- Finding
- Independent corroboration of the designation sequence and milestones: keel laid 22 September 1953 as AM-490, Aggressive-class minesweeper; launched 15 September 1954; reclassified ocean minesweeper MSO-490 7 February 1955; commissioned 16 November 1955 - decommissioned 30 November 1970; 'Recommissioned "Special" 11 February 1972'; recommissioned 6 March 1972 - decommissioned 12 December 1991; struck from the Naval Register 18 March 1992; sold for scrap 18 August 1994. Sponsor Mrs. Norman Wordlund. The ship had no postal facilities; covers bear Long Beach (1959) and Charleston SC (1975) postmarks.
- Verification
- verified
- Role
- context
- Documentation level
- ship_specific
- Accessed
- 2026-10-03
- Study period
- 1953-1994
- Limitations
- Volunteer philatelic museum compilation - corroborating secondary source only; independently confirms the unusual 'Recommissioned Special' status and the 18 August 1994 sale date (matching NavSource against the DANFS transcriber's 15 April 1994). No asbestos content.
- Atlas source
- true
- Evidence ID
- ev-uss-leader-mso490-05
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[6]Era inference built on: DANFS spec block (Aggressive-class AM/MSO); NavSource specifications (Packard ID1700 -> Waukesha diesels, 2 shafts CPP); official NHC history (wooden hulls, nonmagnetic Packard/GM diesels, MSO modernization program); documented yard events (1966 extensive overhaul; 1970-72 modernization overhaul at Harbor Boat Yard, Terminal Island) [other_primary]
- Locator
- DANFS spec block and 1966 overhaul line; NavSource specifications and 1970-72 timeline entries; NHC 'Damn the Torpedoes' pp. 82-83, 95-96
- Finding type
- asbestos_application
- Finding
- A diesel-driven ocean minesweeper built 1953-55 sits inside the Navy's documented asbestos-use era; era-standard applications aboard a vessel of this type and period were engine exhaust lagging, machinery and piping insulation, gaskets, valve packing, electrical insulation, and accommodation finishes (including era-typical vinyl-asbestos decking/tile). As a nonmagnetic wooden-hulled diesel ship she carried no boilers or steam plant - the boiler/turbine lagging pathway of steam vessels does not apply. Two documented yard events - the 9 May - 30 September 1966 extensive overhaul (DANFS) and the 1970-72 modernization overhaul at Harbor Boat Yard, Terminal Island that swapped her Packard diesels for Waukesha engines (NavSource; class program per official history) - are machinery-disturbance windows of the kind in which installed insulation materials were removed and replaced.
- Verification
- inferred
- Role
- supporting
- Documentation level
- class_or_era
- Accessed
- 2026-10-03
- Study period
- 1953-1994
- Population
- Martinac construction trades (1953-55); crew (1955-70, 1972-91); overhaul-period yard and crew populations (1966; 1970-72); NISMF inactivation and 1994 scrapping trades
- Limitations
- Class/era inference only - no hull-specific insulation survey, material list, or work package located for MSO-490. Names era-standard applications and documented overhaul events, not confirmed installed materials and not a confirmed asbestos-handling scope for either yard period. No quantity. Product names are normalized era terms; no manufacturer attribution for this hull.
- Atlas source
- true
- Evidence ID
- ev-uss-leader-mso490-06
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[7]GAO, Navy Efforts To Protect Workers From Asbestos Exposure, HRD-80-2 (Oct 18, 1979) [gao]
- Locator
- GAO product page HRD-80-2 (full text blocked, HTTP 403)
- Finding type
- gov_survey
- Finding
- GAO documented that the Navy used asbestos insulation extensively aboard ships and did not begin substituting alternative insulation materials until the early 1970s - spanning this hull's entire construction (1953-55) and her first commission (1955-70), and touching her 1970-72 modernization.
- Verification
- verified
- Role
- context
- Documentation level
- class_or_era
- Accessed
- 2026-10-03
- Study period
- 1979
- Population
- Navy shipyard workers; asbestos program review
- Limitations
- Program-level documentation; supports era context only, not any fact specific to this hull. Full text not retrieved this session (gao.gov blocks automated fetch, HTTP 403, standing since 2026-09-14) - content via product-page description.
- Atlas source
- true
- Evidence ID
- ev-uss-leader-mso490-07
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[8]Washington State Department of Ecology, cleanup site record: 'JM Martinac Shipbuilding Corp', Tacoma (Facility Site ID 1375, Cleanup Site ID 144) - state Model Toxics Control Act registry; SHARP report (19 Mar 2025, document 163005) [other_primary]
- Locator
- Ecology cleanupsearch site/144 (contaminant table, site status); SHARP report document 163005 (rating 'Low', 2025-03-19)
- Finding type
- environmental_record
- Finding
- Government environmental record for this hull's builder yard: the J. M. Martinac Shipbuilding site at 401 E 15th St, Tacoma is an MTCA cleanup site ('Cleanup Started,' site-use restrictions in effect) with confirmed contaminants limited to metals (other) and arsenic in soil and sediment; the March 2025 SHARP rating is 'Low.' No asbestos is listed among the site's confirmed or suspected contaminants.
- Verification
- verified
- Role
- context
- Documentation level
- class_or_era
- Accessed
- 2026-10-03
- Study period
- 1995-2025 (registry window); yard operating era incl. 1953-55
- Population
- Martinac yard trades (site-level, multi-decade)
- Limitations
- Yard-level environmental record, not a hull record: documents the builder's soil/sediment contamination profile, not materials installed aboard MSO-490 or any other hull built there. Absence of asbestos from the contaminant list does not establish absence of historical asbestos use at the yard - MTCA contaminant listings reflect releases to the environment, not product content. 1950s-era shipyard activity predates the registry (earliest record date 1995).
- Atlas source
- true
- Evidence ID
- ev-uss-leader-mso490-08
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[9]Batch-7604 search ledger (this record): DANFS transcription (losthistory.net/hazegray mirror); NavSource 11/02490; official NHC 'Damn the Torpedoes' (ibiblio); NavalCoverMuseum; NVR (no entry); WA Ecology MTCA site 144 + SHARP 163005; VA BVA web-indexed decisions; CourtListener (blocked); secondary web litigation sweep [other_primary]
- Locator
- search_ledger rows sl-uss-leader-mso490-01 through sl-uss-leader-mso490-12
- Finding type
- historical_record
- Finding
- No qualifying ship-specific asbestos record located: no asbestos survey, abatement contract, hazmat disclosure, museum/curatorial disclosure, or verified litigation naming USS Leader (MSO-490/AM-490) was found in the public sources searched. CAVEAT: CourtListener could not be queried this session - API returned HTTP 429 ('fleet-wide request budget spent'; daily quota exhausted, ~4.6 h to reset) - logged as blocked in search_ledger, not as a negative result. VA BVA web-indexed decisions surfaced no decision naming this hull and search.va.gov was unreachable - an open gap, not a negative. Secondary web sweeps surfaced only law-firm marketing content (navyshipexposure.com 'class equipment pattern' page; mesothelioma.com minesweeper listicle) asserting asbestos aboard without primary sourcing - excluded by source policy.
- Verification
- verified
- Role
- negative_finding
- Documentation level
- ship_specific
- Accessed
- 2026-10-03
- Study period
- 2026-10-03
- Limitations
- Absence of a located public record does not prove absence of asbestos aboard - and the litigation repository search is a genuine open gap (quota-blocked, not run). Deck logs, Harbor Boat Yard and Martinac work packages, NISMF inactivation records, and the 1994 DRMS scrapping contract file are undigitized leads. Does not establish or defeat any claim of exposure or legal eligibility.
- Atlas source
- true
- Evidence ID
- ev-uss-leader-mso490-09
-
[10]Designation cross-check: DANFS and NavSource designation lines (AM-490 -> MSO-490, 7 February 1955, pre-commissioning); NavalCoverMuseum designation table (identical sequence) [other_primary]
- Locator
- DANFS opening paragraph; NavSource header timeline; NavalCoverMuseum designation table
- Finding type
- historical_record
- Finding
- CORRECTION/consolidation note: AM-490 and MSO-490 are one physical hull. The hull was laid down as AM-490 (fleet minesweeper) on 22 September 1953 and reclassified ocean minesweeper MSO-490 on 7 February 1955 - nine months before commissioning. No second vessel ever bore either number; the batch's 'designation mismatch' flag (PRIMARY AM-490 vs canonical MSO-490) resolves to this single hull. Three authoritative sources (DANFS, NavSource, NavalCoverMuseum) carry the identical sequence.
- Verification
- verified
- Role
- correction
- Documentation level
- ship_specific
- Accessed
- 2026-10-03
- Study period
- 1953-1955 (designation window)
- Limitations
- Resolves a cataloging designation mismatch only; not a material or exposure claim. All three sources agree on the 1955-02-07 reclassification date.
- Atlas source
- true
- Evidence ID
- ev-uss-leader-mso490-10