diff --git a/components/results/download.tsx b/components/results/download.tsx
index 6e36aa5..b212d77 100644
--- a/components/results/download.tsx
+++ b/components/results/download.tsx
@@ -4,7 +4,12 @@ import { Box, Flex, Spinner } from 'theme-ui'
 import { Button } from '@carbonplan/components'
 //@ts-expect-error - carbonplan icons types not available
 import { Down, X } from '@carbonplan/icons'
-import { DATA_VERSION, DATA_URLS, LICENSE_INFO } from '@/lib/config'
+import {
+  DATA_VERSION,
+  DATA_URLS,
+  LICENSE_INFO,
+  PARQUET_BUCKET_URL,
+} from '@/lib/config'
 import { useStore } from '@/lib/store'
 import { getGeographyName, getGeoid } from '@/lib/risk-utils'
 import { GeographyKey } from '@/types/location'
@@ -78,8 +83,6 @@ const REGION_TYPES: Partial<Record<GeographyKey, string>> = {
   censusBlock: 'block',
 }
 
-const S3_BUCKET = new URL(DATA_URLS.parquetBase).origin
-
 const DURATION_BUCKETS: [number, string][] = [
   [1000, '<1s'],
   [5000, '1-5s'],
@@ -123,11 +126,11 @@ async function getPartitionUrls(
 ): Promise<string[]> {
   const stateFips = geoid.slice(0, 2)
   const countyFips = geoid.slice(2, 5)
-  const prefix = DATA_URLS.parquetBase.replace(S3_BUCKET + '/', '')
+  const prefix = DATA_URLS.parquetBase.replace(PARQUET_BUCKET_URL + '/', '')
   const partitionPrefix = `${prefix}/state_fips=${stateFips}/county_fips=${countyFips}/`
 
   const res = await fetch(
-    `${S3_BUCKET}/?list-type=2&prefix=${partitionPrefix}`,
+    `${PARQUET_BUCKET_URL}/?list-type=2&prefix=${partitionPrefix}`,
     { signal },
   )
   const doc = new DOMParser().parseFromString(
@@ -138,7 +141,7 @@ async function getPartitionUrls(
   const urls: string[] = []
   for (const el of doc.querySelectorAll('Contents > Key')) {
     const key = el.textContent
-    if (key?.endsWith('.parquet')) urls.push(`${S3_BUCKET}/${key}`)
+    if (key?.endsWith('.parquet')) urls.push(`${PARQUET_BUCKET_URL}/${key}`)
   }
 
   if (urls.length === 0) {
diff --git a/components/results/regional-risk.tsx b/components/results/regional-risk.tsx
index 1b864f0..fa515eb 100644
--- a/components/results/regional-risk.tsx
+++ b/components/results/regional-risk.tsx
@@ -8,7 +8,7 @@ import { LngLatBounds } from 'maplibre-gl'
 import { getGeographyRisk, getBoundingBox } from '@/lib/risk-utils'
 import { useStore } from '@/lib/store'
 import {
-  DATA_VERSION,
+  DATA_URLS,
   GEOGRAPHY_ATTRIBUTE_KEYS,
   GEOGRAPHY_MIN_ZOOM,
   STATISTICS_PATHS,
@@ -345,14 +345,14 @@ const RegionalRisk = () => {
                     label='CSV'
                     loading={false}
                     disabled={false}
-                    href={`https://s3.us-west-2.amazonaws.com/us-west-2.opendata.source.coop/carbonplan/carbonplan-ocr/output/fire-risk/vector/production/${DATA_VERSION}/region-analysis/${STATISTICS_PATHS[geographyLevel]}/stats.csv`}
+                    href={`${DATA_URLS.regionAnalysisBase}/${STATISTICS_PATHS[geographyLevel]}/stats.csv`}
                     ariaLabel={`Download summary data as CSV`}
                   />
                   <DownloadButton
                     label='GeoJSON'
                     loading={false}
                     disabled={false}
-                    href={`https://s3.us-west-2.amazonaws.com/us-west-2.opendata.source.coop/carbonplan/carbonplan-ocr/output/fire-risk/vector/production/${DATA_VERSION}/region-analysis/${STATISTICS_PATHS[geographyLevel]}/stats.geojson`}
+                    href={`${DATA_URLS.regionAnalysisBase}/${STATISTICS_PATHS[geographyLevel]}/stats.geojson`}
                     ariaLabel={`Download summary data as GeoJSON`}
                   />
                 </Flex>
diff --git a/lib/config.ts b/lib/config.ts
index 9dd03ab..4593494 100644
--- a/lib/config.ts
+++ b/lib/config.ts
@@ -2,26 +2,42 @@ export const BASE_PATH = '/research/climate-risk'
 
 export const DATA_VERSION = 'v1.1.0'
 
+// Source Coop's bucket name contains dots, so only path-style URLs work —
+// virtual-hosted style (bucket.s3.amazonaws.com) fails TLS validation.
+const S3_BUCKET_URL =
+  'https://s3.us-west-2.amazonaws.com/us-west-2.opendata.source.coop'
+
+const dataUrl = (kind: 'vector' | 'pyramid', path: string) =>
+  `${S3_BUCKET_URL}/carbonplan/carbonplan-ocr/output/fire-risk/${kind}/production/${DATA_VERSION}/${path}`
+
 export const DATA_URLS = {
   vector: {
     buildings:
       process.env.NEXT_PUBLIC_BUILDING_URL ??
-      `https://carbonplan-ocr.s3.amazonaws.com/output/fire-risk/vector/production/${DATA_VERSION}/pmtiles/buildings.pmtiles`,
+      dataUrl('vector', 'pmtiles/buildings.pmtiles'),
     regions:
       process.env.NEXT_PUBLIC_REGIONS_URL ??
-      `https://carbonplan-ocr.s3.amazonaws.com/output/fire-risk/vector/production/${DATA_VERSION}/pmtiles/regions.pmtiles`,
+      dataUrl('vector', 'pmtiles/regions.pmtiles'),
     buildingPoints:
       process.env.NEXT_PUBLIC_BUILDING_POINTS_URL ??
-      `https://carbonplan-ocr.s3.amazonaws.com/output/fire-risk/vector/production/${DATA_VERSION}/pmtiles/building_centroids.pmtiles`,
+      dataUrl('vector', 'pmtiles/building_centroids.pmtiles'),
   },
   raster:
-    process.env.NEXT_PUBLIC_RISK_ZARR_URL ??
-    `https://carbonplan-ocr.s3.amazonaws.com/output/fire-risk/pyramid/production/${DATA_VERSION}/pyramid.zarr`,
+    process.env.NEXT_PUBLIC_RISK_ZARR_URL ?? dataUrl('pyramid', 'pyramid.zarr'),
   parquetBase:
     process.env.NEXT_PUBLIC_GEOPARQUET_URL ??
-    `https://carbonplan-ocr.s3.us-west-2.amazonaws.com/output/fire-risk/vector/production/${DATA_VERSION}/geoparquet/buildings.parquet`,
+    dataUrl('vector', 'geoparquet/buildings.parquet'),
+  regionAnalysisBase: dataUrl('vector', 'region-analysis'),
 }
 
+// Root for ListObjectsV2 requests against whichever bucket holds the parquet.
+// Path-style URLs put the bucket after the host; anything else is virtual-hosted.
+export const PARQUET_BUCKET_URL = DATA_URLS.parquetBase.startsWith(
+  S3_BUCKET_URL,
+)
+  ? S3_BUCKET_URL
+  : new URL(DATA_URLS.parquetBase).origin
+
 export const LICENSE_INFO = {
   provider: 'CarbonPlan',
   termsOfAccess:
diff --git a/pages/_document.tsx b/pages/_document.tsx
index bd5b92f..777631c 100644
--- a/pages/_document.tsx
+++ b/pages/_document.tsx
@@ -21,10 +21,7 @@ class MyDocument extends Document {
             rel='preconnect'
             href='https://carbonplan-maps.s3.us-west-2.amazonaws.com'
           />
-          <link
-            rel='preconnect'
-            href='https://carbonplan-ocr.s3.amazonaws.com'
-          />
+          <link rel='preconnect' href='https://s3.us-west-2.amazonaws.com' />
           <link rel='preconnect' href='https://fonts.carbonplan.org' />
         </Head>
         <body>