diff --git a/src/BaseAPI.js b/src/BaseAPI.js
index 8fce166..b0219b2 100644
--- a/src/BaseAPI.js
+++ b/src/BaseAPI.js
@@ -14,6 +14,7 @@ const scorm12_error_codes = ErrorCodes.scorm12;
  * abstract, and never initialized on it's own.
  */
 export default class BaseAPI {
+  #initialized = false;
   #timeout;
   #error_codes;
   #settings = {
@@ -111,6 +112,9 @@ export default class BaseAPI {
       callbackName: String,
       initializeMessage?: String,
       terminationMessage?: String) {
+    if (this.#initialized) return global_constants.SCORM_TRUE;
+
+    this.#initialized = true;
     if (this.selfReportSessionTime) {
       this.cmi.setStartTime();
     }