HCMs that have cleared HITL street view verification (or are queued for it) and warrant ground-truth assessment by a structural engineer (type-2 hypothesis) or environmental scientist (type-1 hypothesis). this is the most expensive tier of work in the audit: a phase i environmental site assessment runs $3,000-5,000; a structural condition survey on a single-family residence is $1,500-2,500; on a larger commercial / industrial parcel it is $3,000-8,000.
queue currently contains 21 entries totalling an estimated $44,202-$49,200 in field assessment cost. the queue is a yaml file at content/HCM-1200/site_visit_queue.yaml — the user edits it as candidates clear HITL review.
The three-tier workflow
Tier 1 — GIS analysis (automated, free)
contextual signals from cal OEHHA CalEnviroScreen 4.0 (cumulative pollution burden by census tract), city of la Mills Act appendix a (per-property subsidy contracts + equity tiers), LADBS permit history, 311 CSR cases, code complaints. ranks ~1295 active HCMs into typed candidate lists. described at /HCM-1200.
Tier 2 — HITL street view verification (manual, free)
human reviewer opens the fresh Google street view deep link per candidate and pans to find the building. confirms or rejects visible distress indicators: boarded windows, tarped roof, vegetation overgrowth, chain-link perimeter, abandoned signage. confirmed cases move to tier 3. described at /HCM-1200/candidates.
Tier 3 — site visit by domain expert (paid, gated)
structural engineer or environmental scientist physically visits the property to produce a defensible diagnosis. expensive ($1.5k-25k per property depending on scope). access requires owner consent or a city / nonprofit facilitation pathway. produces a phase i environmental site assessment or structural condition report that can be filed with the cultural heritage commission as part of any subsequent action (delisting petition, adaptive reuse proposal, restoration subsidy application).
Active queue
21 entries$44,202-$49,200 est. field-assessment cost2 type-119 type-2
cityOwned by City of LA (decommissioned municipal facility under Recreation and
Parks or General Services Department). Direct outreach to the office of the
Council District 14 representative + LA OHR (Melissa Jones, Ken Bernstein)
for coordinated access. CHC site visit precedent exists.
estimated cost
~$5,000-8,000 (Phase I ESA ~$3-5k; structural condition survey ~$2-3k).
Phase II soil sampling separate, $10-25k if Phase I flags Recognized
Environmental Conditions, which it almost certainly will.
HITL findings
reviewed 2026-05-12 by claude vision (claude-sonnet-4-6, 4-image street view pass)Vision classification: condition=abandoned. Five distress indicators
across both Type-1 and Type-2 vocabularies: chain_link_perimeter,
rail_spur_remnant, loading_dock, boarded_windows, vegetation_overgrowth.
This is the only HCM in the 78-candidate vision sweep classified as
"abandoned" — every other candidate came back well_maintained, fair,
or partially visible. The visible distress confirms the GIS-derived
Type-1 verdict (contamination probability 0.73) and adds Type-2 signal
the rubric had not surfaced (boarded windows imply the structure itself
is being protected from the elements while not in active use).
visible graffiti2023-12-01 · google earth aerial · fronthypothesisVisible graffiti on the front / Avenue 19 elevation and roof-edge massing in 2023 aerial view. Hypothesis: still present, same pattern.
evidence 1 ↗
visible graffiti2023-12-01 · google earth aerial · backobservedVisible graffiti on the back / LA River and rail-side elevation in 2023 aerial view.
evidence 1 ↗
active rail context2023-12-01 · google earth aerial · backobservedRail cars visible immediately behind the jail along the LA River side, confirming active freight / rail-adjacent context at the rear edge of the parcel.
evidence 1 ↗
depot within 1km west2023-12-01 · google maps satellite · maphypothesisOptional contextual note: depot / rail-yard complex visible roughly 1 km due west of the jail, reinforcing the Type-1 rail / industrial contamination-overhang hypothesis.
deterioration since 20202025-10-01 · google street view · frontobservedCompared with the December 2020 front Street View, the October 2025 front view shows a visibly worse vandalism / envelope condition: more broken or missing window panes across the upper floors, new or more legible ground-level graffiti on the south/front wall and doors, and persistent boarded ground-floor openings. The building remains inactive and unsecured-looking despite continued city ownership / public-facility signage context in the 2020 baseline.
evidence 1 ↗evidence 2 ↗
notes
Lincoln Heights Jail — 1.7 ac in a TPA tier 3 tract backing onto the LA River.
Type-1 contamination probability 0.84 (top-decile cumulative pollution burden
tract). A century of correctional use means asbestos, lead paint, possible
mercury (early sanitation systems), and likely soil contamination at the
perimeter (vehicle fuel, dumping). Structural condition is the gating
variable for whether facade-incorporation reuse is viable vs. full
replacement. CHC review will require both reports.
HCM-790type-1pending HITL street view reviewenvironmental scientiststructural engineer
ownership
privateParcel held by a private development entity that has held the site
speculatively for over a decade. LA OHR has standing to facilitate access
via the HCM designation. Alternative pathway: LA Conservancy field
coordinator can request a walk-through under the conservancy's
endangered-properties program.
estimated cost
~$6,000-10,000 (Phase I ESA + portal masonry condition assessment + rail
substation contamination). Higher than typical Phase I because of the
rail-era contamination context.
notes
Belmont Tunnel + Toluca Substation — 1 ac at TPA tier 1, walking distance
to two metro rail lines. Type-1 contamination probability 0.80. Decades
of rail / electrical substation use means transformer-era PCBs probable,
creosote-treated ties around perimeter, hydrocarbon contamination from
diesel locomotive fueling. Portal masonry condition determines whether
the artifact can be retained as a plaza feature in any future development.
privateMultifamily apartment building on Burnside Ave. Owner outreach via LA
Conservancy's outreach coordinator or direct via Assessor records.
Given the "permanently closed" listing on the sibling property, owner
is likely in dispute with the city or has abandoned active operation
— outreach should anticipate an unresponsive owner. CHC notice of
intent may be needed for the structural assessment.
estimated cost
~$2,500 (structural condition survey for a small multifamily)
HITL findings
reviewed 2026-05-12 by alexCluster confirmation via Google Maps: 616 Burnside Ave Apartments (the
property between HCM-423 at 607 and HCM-424 at 626) shows status
"Permanently closed" with a public-facing listing still up but no
current operation. Strongly suggests the entire block of HCM-protected
apartment buildings is in a state of non-operation. The "permanently
closed" status combined with the HCM designation is the textbook
Type-2 trapped pattern: building cannot operate (closed), cannot be
demolished (HCM-protected), cannot be substantially altered (HPOZ /
designation covenants). Site visit by structural engineer is the next
step to determine whether the closure is operational/economic vs
structural, and what the path forward is.
notes
One of three Burnside Avenue apartment buildings (423, 424, 425) designated
1989, all with 2 open CSR cases, no recent permits. The cluster pattern is
now HITL-confirmed via the neighboring 616 Burnside Ave "permanently closed"
listing. This is the strongest current Type-2 test case in the audit.
privateSame as HCM-423 (paired property — likely common owner)
estimated cost
~$2,500
HITL findings
reviewed 2026-05-12 by alexHCM-424 (626 S Burnside Ave) is one block from 616 Burnside Ave
Apartments (Google Maps status: permanently closed). Same building
type, same HCM-listed designation year (1989), same signal pattern
as HCM-423 (2 open CSR, no recent permits). Cluster-level Type-2
confirmation by spatial association.
notes
Sibling to HCM-423; same signal pattern, now HITL-cluster-confirmed.
Inspection should be paired with 423 + 425 for efficiency.
privateSame as HCM-423 (paired property — likely common owner)
estimated cost
~$2,500
HITL findings
reviewed 2026-05-12 by alexHCM-425 (636 S Burnside Ave) is two blocks from 616 Burnside Ave
Apartments (Google Maps status: permanently closed). Same cluster.
Same signal pattern as HCM-423 and HCM-424. Cluster-level Type-2
confirmation by spatial association.
notes
Sibling to HCM-423; same signal pattern, now HITL-cluster-confirmed.
Inspection should be paired with 423 + 424 for efficiency. If all three
confirm structural distress, this block becomes the strongest test case
for the Type-2 "trapped" hypothesis.
privateSingle-family residence on S Alvarado in Westlake. Standard owner
outreach via LA Conservancy or direct. The cluster pattern with HCM-327
suggests a single owner — outreach to one likely reaches both.
reviewed 2026-05-12 by claude vision (claude-sonnet-4-6, 4-image street view pass)Vision classification: condition=distressed. Four indicators:
boarded_windows, plywood_patches, structural_sagging, vegetation_overgrowth.
Adjacent to HCM-327 Thomas Potter Residence at 1135-1141 S Alvarado;
both show the same indicator set. Strong cluster signal — likely common
owner or block-level distress on the 1100 block of S Alvarado.
notes
August Winstel Residence, designated 1987. The strongest single distress
verdict in the broader field-reconnaissance sweep (4 indicators, including
the rare structural_sagging signal). Pair the site visit with HCM-327.
privateLikely same owner as HCM-328 — paired outreach
estimated cost
~$1,800 (paired with HCM-328)
HITL findings
reviewed 2026-05-12 by claude vision (claude-sonnet-4-6, 4-image street view pass)Vision classification: condition=distressed. Three indicators:
boarded_windows, plywood_patches, vegetation_overgrowth.
Adjacent to HCM-328 August Winstel Residence (1147 S Alvarado), same
condition. Cluster-level finding.
notes
Thomas Potter Residence, designated 1987. Sibling to HCM-328.
privateSingle-family residence at 4020-4026 Bluff Place. Owner likely
non-responsive given the fire damage going unaddressed. CHC notice
of intent to inspect may be needed.
estimated cost
~$2,500 (single-family + post-fire condition assessment is moderately complex)
HITL findings
reviewed 2026-05-12 by claude vision (claude-sonnet-4-6, 4-image street view pass)Vision classification: condition=distressed. Indicators:
fire_damage, structural_sagging, vegetation_overgrowth.
The only "fire_damage" verdict in the entire field-reconnaissance
sweep — visible fire scorching left unaddressed, combined with
structural sagging. Textbook Type-2 trapped pattern: building can't
be lived in (fire damage), can't be demolished (HCM), can't be
substantially altered (designation covenants).
notes
Wilbur F. Wood House, designated 1992. The rarest distress pattern in
the sweep. Highest individual-property priority among the new finds.
privateCharles B. Booth Residence + Carriage House at 824-826 S Bonnie Brae.
Standard owner outreach via LA Conservancy.
estimated cost
~$2,000 (single-family + carriage house outbuilding)
HITL findings
reviewed 2026-05-12 by claude vision (claude-sonnet-4-6, 4-image street view pass)Vision classification: condition=distressed. Indicators:
tarped_roof, vegetation_overgrowth.
Tarped_roof is the strongest single distress signal in the
vocabulary — visible roof damage left unaddressed for the duration
of Google's Street View capture window.
notes
Designated 1990. Bonnie Brae cluster with HCM-99 (1036-1038 S Bonnie Brae).
HCM-482type-2pending HITL street view reviewstructural engineer
ownership
privateSingle-family residence on South Avenue 49 in Highland Park. Standard
private-owner outreach. Lower priority than the Burnside cluster because
only 1 open CSR (vs 2 per Burnside property) and earlier work suggested
this may still be occupied.
Bent House. Earlier flagged as a false positive in BLOCKING_REDEVELOPMENT;
vacancy unconfirmed. Site visit would resolve the ambiguity definitively.
Lower priority because the property may simply be a quiet occupied SFR
with one routine CSR case.
Scope-of-work templates
templates the user can adapt and send to a structural engineer or environmental scientist when commissioning a site visit. defines what a defensible tier-3 assessment includes; the reports should be filable with the la cultural heritage commission as evidence in any subsequent administrative action.
Environmental scientist — phase i environmental site assessment (asTM e1527-21)
standard scope for any type-1 candidate. ~$3,000-5,000 turn-around 2-4 weeks. produces a defensible recognized environmental conditions (rec) determination.
records review — federal EnviroStor / nplis, state DTSC EnviroStor, calgem oil & gas wells, regional water board cleanups, fire department incident records, sanborn fire insurance maps, historic aerial imagery (pre-1980), city directories.
site reconnaissance — walking perimeter and accessible interior, observing for distressed vegetation, stained soil, dry wells, transformer / electrical equipment, abandoned underground storage tank vent pipes, suspect asbestos-containing materials (vinyl tile, pipe insulation, popcorn ceiling), suspect lead-based paint, abandoned drums or containers.
adjacent property assessment — same scope applied to neighboring parcels (250 ft radius typical for an HCM).
regulatory interviews — owner / occupant if accessible; OHR planner; dbs district inspector.
findings + opinion — list of identified recs, historical recs, controlled recs, with photo documentation. opinion on whether a phase ii (soil + groundwater sampling) is warranted.
deliverable — bound report, fileable with CHC + city OHR, valid for 180 days under astm e1527-21.
Structural engineer — historic building condition assessment
standard scope for any type-2 candidate. ~$1,500-3,000 for a single-family residence, $3,000-8,000 for larger or more complex buildings. produces a code-defensible structural condition opinion.
visual inspection of primary structure — foundation (settlement, cracking, water intrusion), framing (sagging, rot, fire damage, termite), roof structure (deflection, water damage), bearing walls, lateral-force-resisting elements.
cost estimate to stabilize vs cost to restore vs cost to replace — three-tier number with confidence interval. the gating decision for any subsequent CHC petition (retain / facade-incorporation / delist + replace) turns on this trio.
deliverable — stamped report by ca-licensed structural engineer (s.e. or p.e.), fileable with CHC + dbs.
Access pathway templates
most HCMs are privately owned; site access requires owner consent or a facilitating third-party. these are the available pathways:
City-owned HCM — direct city access
for properties owned by the city of la (most decommissioned civic infrastructure — HCM-587 lincoln heights jail falls here, owned by recreation and parks or general services). contact: council district representative's office + la office of historic resources (melissa.jones@lacity.org / lambert.giessinger@lacity.org / ken.bernstein@lacity.org) for coordinated access. the CHC has standing to authorize structural / environmental assessments on city-owned HCMs as part of routine custodial review.
Private-owner HCM with active Mills Act contract — city standing via covenants
Mills Act contracts include maintenance and inspection covenants that grant the city limited inspection authority. OHR can request a site visit under the contract terms; private owners typically cooperate to avoid contract default. the inspection scope is narrower than a full phase i / structural assessment but can establish access and frame a fuller assessment.
Private-owner HCM without subsidy — direct outreach + conservancy facilitation
for private HCMs without a Mills Act contract, the access pathway is direct owner outreach. recommended sequence: (1) la conservancy outreach coordinator (la-based nonprofit with decades of preservation-owner relationships) can write a brokered letter of inquiry, (2) failing that, direct certified letter from a credentialed researcher with academic or city affiliation, (3) failing that, the CHC can issue a notice of intent to inspect under LAMC 22.171 et seq. but this is adversarial and slows everything. always prefer the conservancy path.
Private-owner refuses access — administrative-record alternative
if the owner declines access, the type-1 / type-2 diagnosis can still be advanced via administrative record: LADBS substandard / unsafe building registry filings, DTSC EnviroStor history, lafd fire incident reports, county assessor delinquency, certified-mail correspondence. weaker than a site visit but defensible enough to file as part of a CHC delisting petition or adaptive reuse proposal.