diff --git a/src/lang/wasm.ts b/src/lang/wasm.ts
index b28da9b90..e8d14bae2 100644
--- a/src/lang/wasm.ts
+++ b/src/lang/wasm.ts
@@ -166,7 +166,7 @@ interface RawProgramMemory {
  * in the future.
  */
 export class ProgramMemory {
-  environments: Environment[]
+  private environments: Environment[]
   private currentEnv: EnvironmentRef
   private return: KclValue | null