Catalog of primary research sources and data feeds the HCM-1200 audit draws on, plus the registries and reference materials not yet integrated but worth pursuing. Big Orange Landmarks (Bariscale, 2007-2011) is the single best independent narrative source for the ~140 HCMs it covered before going dormant — his photography from that era is a fixed "then" baseline for the deterioration comparisons the audit makes against current imagery.
Primary research sources
Independent and institutional sources for narrative, case-file, and advocacy context per HCM.
independent blog by floyd b. bariscale (2007-2011) documenting individual los angeles historic-cultural monuments. posts follow hcm numerical designation (e.g., "no. 230 — villa maria"). bariscale worked sequentially through the register and covered hcm-1 through hcm-230 contiguously (100% of that range, 230 hcms total, 241 posts including event announcements) before the blog went dormant in june 2011. each post includes original photography by bariscale, archival images from the la public library, and historical research drawing on la times reporting and primary sources.
how the audit uses it: the single best independent narrative source for hcm-1 through hcm-230 (~17% of all active hcms). bariscale's photography from 2007-2011 is particularly valuable as a fixed "then" baseline for the audit's before/after visual-deterioration comparisons against current google street view imagery. editorial stance is openly preservationist. as of 2026-05, integrated as a per-hcm cross-reference: any hcm in the 1-230 range shows a "big orange landmarks ↗" link from its detail page (scripts/hcm-1200/fetch-big-orange-landmarks.mjs builds the lookup; content/hcm-1200/big_orange_landmarks.json stores it).
caveats: inactive since june 2011. photos are bariscale's personal work (flickr-hosted) — link out, do not republish. hcms designated after ~2011 (anything past hcm-230) are not covered.
the official city office maintaining the hcm register, processing nominations, preparing chc staff reports, and administering mills act contracts + hpoz programs. source of the canonical hcm list, the chc case files, the mills act appendix a aecom equity-tier data, and the historic-resources survey data (surveyla).
how the audit uses it: canonical source of truth for the audit's hcm list and mills act data. the chc staff reports (linked from each case file) are the primary substantive document per designation. surveyla contextualizes individual hcms against neighborhood-scale historic-resources surveys.
per-case chc staff recommendation reports + nomination forms + supporting documentation, posted to the la planning agenda system. provides the official narrative and findings for each designation, including criterion claims, alteration history, owner consent status, and the staff recommendation.
how the audit uses it: used as the primary procedural source for individual case studies (hcm-587, cadet records). case file numbers follow the pattern chc-yyyy-nnnn-hcm. the cadet records area study (chc-2024-1629-hcm) is the example of an active case where the audit's lens has been applied pre-designation.
caveats: case files are published to the meeting agenda system and may move. always cite the case number and hearing date; do not deep-link to the planning document store.
largest nonprofit historic preservation advocacy organization in la. maintains the modern committee, historic resources at risk reports, an active walking-tour program, and a position on most major demolition controversies. key institutional counterparty for any delisting conversation.
how the audit uses it: operates institutionally with a preservation-bias by mandate. the audit cites conservancy positions on individual cases for context but does not treat their recommendations as authoritative. critical to engage as a stakeholder for any actual delisting petition (e.g., hcm-587) — opposition from the conservancy is the principal political risk for the demolition pathway.
independent walking + bus tour operator (kim cooper + richard schave) covering la historic and cultural sites. maintains a substantive blog with primary-source research on individual hcms and adjacent properties. particularly strong on downtown, skid row, and underdocumented la history.
how the audit uses it: a useful tertiary source for individual hcms that fall outside bariscale's coverage window. esotouric has been active continuously since 2007.
Integrated data feeds
Open-data sources currently feeding the audit's scorer + classifier pipeline (scripts/HCM-1200/lib/fetchers/).
la department of building and safety permit history + code complaint records via the city open-data portal. primary signal for inferring vacancy + active construction + deterioration.
how the audit uses it: see scripts/hcm-1200/lib/fetchers/. the vacancy-inference rule (lib/vacancy.mjs) was tightened after the hcm-406 + hcm-482 false-positive cases — now requires ≥3 code complaints with old permits, ≥8 complaints regardless of permit history, ≥3 open csr cases without permit data, or a manual override.
la 311 case records (graffiti, dumping, encampment, abandoned vehicle, etc.) via city open data. externality-load signal per parcel.
how the audit uses it: feeds the d-axis (externality load) score and the vacancy inference rule. geographic radius around the parcel is configurable; current rule uses ~150 ft.
california department of toxic substances control database of contaminated sites, cleanups, hazardous-waste facilities, and brownfield candidates. primary signal for type-1 contamination overhang.
how the audit uses it: distance from parcel to nearest envirostor site is computed per hcm, with counts of sites within 250m / 500m / 1000m. confirmed contaminants of concern (coc) extracted where available. the hcm-587 audit data shows nearest site at 404m (victor industrial battery), with 9 sites within 1000m. feeds type1_contamination_probability.
oehha composite environmental-justice index combining pollution burden + population vulnerability, percentile-ranked per census tract.
how the audit uses it: tract-level percentiles for cleanups, groundwater threats, hazardous waste, toxic releases, lead, and the composite score are pulled per hcm. hcm-587 sits at the 98th percentile composite (decile 10) — one of the highest-ej-burden tracts in california.
per-contract mills act dataset from the 2023 aecom equity analysis appendix. provides equity-tier classification per hcm with an active mills act contract.
how the audit uses it: 930 of 931 active contracts have equity tier assigned. drives the load_bearing vs subsidy_not_load_bearing split in the necessity classifier — subsidy on a low barriers / low-to-medium barriers tract is the "subsidies for the already saved" pattern.
wikipedia article presence + 12-month pageview count as a proxy for tourist-currency / public-awareness of an hcm.
how the audit uses it: feeds the b-axis (tourist currency) score. watts towers, hollywood sign, la brea tar pits are at the high end (>100k pageviews); most hcms are below 1k.
the citywide historic resources survey conducted 2010-2017, producing community-plan-level inventories of eligible historic resources (hrg-group of 88 categories) that exist independent of formal hcm designation.
how the audit uses it: surveyla findings are useful for contextualizing individual hcms against the broader population of eligible-but-undesignated resources. not currently integrated; integration would let the audit answer "of n similar buildings in the surveyla inventory, how many are hcm-designated and how many are not?" — the relative-rarity question.
Peer-jurisdiction sources
Other US municipal landmark commissions used in the peer-cities comparison.
annual reports, designation reports, permit records, and the discover nyc landmarks map covering ~37,800 individual designations + 156 historic districts. the benchmark us municipal-preservation regime.
how the audit uses it: used as the headline comparison in the peer-cities page. lpc was created in 1965 in direct response to the demolition of penn station; their designation rate and political insulation set the upper bound for us municipal preservation reach.
san francisco article 10 (individual landmarks) + article 11 (downtown conservation districts) commission, including graded protection categories (i-v) and the 270-day demolition delay ordinance.
how the audit uses it: closest ca peer to la — same mills act framework, similar commission → council structure. sf's article 11 categorical grading is a useful model for graded hcm protection.
chicago landmarks designation + the broader 1996 chicago historic resources survey (chrs) orange-rated demolition-delay layer. prentice women's hospital case (2012-13) is the most relevant procedural precedent for la delisting.
how the audit uses it: the chrs orange-rated layer is a useful model — a broad demolition-delay net beneath the narrower formal-landmark layer. la does not currently have an analogous secondary protection tier.
Not-yet-integrated registries
Data feeds that would meaningfully improve the audit's coverage if access were available. Listed roughly in priority order.
per-property registry of substandard or unsafe buildings — the regulatory companion to the vacant-building maintenance program. would surface type-2 (residential structural damage trapped under preservation covenants) cases directly.
why integration would help: not exposed as a public spatial open-data dataset. integration requires either an ladbs data request, public-records-act request, or scraping the published case lists. high value for the trapped_residential classifier — would let the "likely" tier resolve to "confirmed."
la dbs registry of vacant buildings under the maintenance ordinance. owners of vacant structures are required to register and maintain compliance with the property.
why integration would help: like the substandard registry, not publicly exposed as a spatial dataset. direct integration would meaningfully expand the blocking_redevelopment count by surfacing vacant hcms that the current ladbs-permit-based vacancy inference rule cannot detect.
property tax payment status per parcel. multi-year tax delinquency on an hcm is a strong proxy for owner distress and potential vacancy.
why integration would help: not publicly exposed as a spatial dataset; integration is non-trivial. pair with vacancy registry would significantly improve the audit's ability to surface trapped type-2 cases.
active electric + water service connections per parcel. zero active services for 12+ months is a strong vacancy signal.
why integration would help: customer data is privacy-restricted; aggregate parcel-level service status is not publicly available. would require a formal data-sharing agreement with ladwp.
la times reporting on individual hcm cases, demolition controversies, designation hearings, and preservation politics. particularly valuable for the procedural-precedent cases (ambassador hotel 2005, 6th street viaduct 2016, sears mail-order 2019, prentice hospital 2013 in chicago).
why integration would help: cited in case studies where relevant. full archive access via proquest is not currently available to the audit; public archive coverage from ~2000 forward is usable.