diff --git a/.github/workflows/container.yml b/.github/workflows/container.yml
index 950f3bf..b6cec52 100644
--- a/.github/workflows/container.yml
+++ b/.github/workflows/container.yml
@@ -29,5 +29,5 @@ jobs:
           cache-from: type=gha,scope=ckan_geoconnex_bulk_runner
           platforms: linux/amd64
           cache-to: type=gha,mode=max,scope=ckan_geoconnex_bulk_runner
-        env:
-          NAMESPACE: ${{ matrix.namespace }}
+          build-args:
+            - NAMESPACE=${{ matrix.namespace }}
diff --git a/bulk_loader/Dockerfile b/bulk_loader/Dockerfile
index 87aa04f..4a3521a 100644
--- a/bulk_loader/Dockerfile
+++ b/bulk_loader/Dockerfile
@@ -2,6 +2,7 @@ FROM rust:1.96 AS builder
 WORKDIR /app
 RUN rustup set profile minimal
 COPY . .
+ARG NAMESPACE
 RUN cargo build -p bulk_loader --release
 
 FROM ubuntu:latest