diff --git a/src/dbos-executor.ts b/src/dbos-executor.ts
index 1c1dcbf00..1b788fa0c 100644
--- a/src/dbos-executor.ts
+++ b/src/dbos-executor.ts
@@ -167,7 +167,11 @@ export class DBOSExecutor implements DBOSExecutorContext {
     // Set configured environment variables
     if (config.env) {
       for (const [key, value] of Object.entries(config.env)) {
-        process.env[key] = value;
+        if (typeof value === "string") {
+          process.env[key] = value;
+        } else {
+          console.warn(`Invalid value type for environment variable ${key}: ${typeof value}`);
+        }
       }
     }
 
diff --git a/src/dbos-runtime/config.ts b/src/dbos-runtime/config.ts
index d73289a44..cfcab7656 100644
--- a/src/dbos-runtime/config.ts
+++ b/src/dbos-runtime/config.ts
@@ -49,7 +49,7 @@ export interface ConfigFile {
 export function substituteEnvVars(content: string): string {
   const regex = /\${([^}]+)}/g; // Regex to match ${VAR_NAME} style placeholders
   return content.replace(regex, (_, g1: string) => {
-    return process.env[g1] || ""; // If the env variable is not set, return an empty string.
+    return process.env[g1] || '""'; // If the env variable is not set, return an empty string.
   });
 }
 
diff --git a/tests/dbos-runtime/config.test.ts b/tests/dbos-runtime/config.test.ts
index 3e0400d78..1d8d5a876 100644
--- a/tests/dbos-runtime/config.test.ts
+++ b/tests/dbos-runtime/config.test.ts
@@ -196,12 +196,14 @@ describe("dbos-config", () => {
           app_db_name: 'some DB'
         env:
           FOOFOO: barbar
+          RANDENV: \${SOMERANDOMENV}
       `;
       jest.restoreAllMocks();
       jest.spyOn(utils, "readFileSync").mockReturnValue(localMockDBOSConfigYamlString);
       const [dbosConfig, _dbosRuntimeConfig]: [DBOSConfig, DBOSRuntimeConfig] = parseConfigFile(mockCLIOptions);
       const dbosExec = new DBOSExecutor(dbosConfig);
       expect(process.env.FOOFOO).toBe("barbar");
+      expect(process.env.RANDENV).toBe(""); // Empty string
       // We didn't init, so do some manual cleanup only
       clearInterval(dbosExec.flushBufferID);
       await dbosExec.telemetryCollector.destroy();