diff --git a/src/worker/src/xcecd_worker_utils.c b/src/worker/src/xcecd_worker_utils.c
index e88065f7..cf00ff37 100644
--- a/src/worker/src/xcecd_worker_utils.c
+++ b/src/worker/src/xcecd_worker_utils.c
@@ -297,6 +297,12 @@ void remove_worker(xcecd_worker_t** worker_list, int worker_pid)
         FREEUP(worker->job_cmd);
         FREEUP(worker->job_info.pidinfo.pids);
         FREEUP(worker->job_exdata);
+        /* bug-1866: every other string add_worker() copies */
+        FREEUP(worker->launch_type);
+        FREEUP(worker->q_pre_exec);
+        FREEUP(worker->q_post_exec);
+        FREEUP(worker->job_pre_exec);
+        FREEUP(worker->job_post_exec);
         FREEUP(worker);
     }
 }
diff --git a/src/worker/testsuite/test_finished_job_retention.c b/src/worker/testsuite/test_finished_job_retention.c
index ff60612d..d5262105 100644
--- a/src/worker/testsuite/test_finished_job_retention.c
+++ b/src/worker/testsuite/test_finished_job_retention.c
@@ -371,6 +371,55 @@ static void test_unhealthy_connection_suspends_expiry(void)
         70005, finish_time_ms + window_ms + 100, &out));
 }
 
+/* ════════════════════════════════════════════════════════════════════════
+ * bug-1866: remove_worker() must free every string add_worker() copied
+ * out of the startinfo. This suite runs with detect_leaks=0, so compare
+ * ASAN's live-heap byte count across an add/remove round trip instead.
+ * ════════════════════════════════════════════════════════════════════════ */
+
+#ifdef __SANITIZE_ADDRESS__
+/* from <sanitizer/allocator_interface.h>, which the nix toolchain lacks */
+size_t __sanitizer_get_current_allocated_bytes(void);
+
+static void add_remove_full_startinfo_worker(int pid, uint64_t jobid)
+{
+    xcecd_worker_t* list      = NULL;
+    job_startinfo_t startinfo = {
+        .exechome      = (char*)"/home/u",
+        .execcwd       = (char*)"/home/u/run",
+        .execuser      = (char*)"u",
+        .cmdline       = (char*)"sleep 1",
+        .exdata        = (char*)"exdata",
+        .launch_type   = (char*)"openmpi",
+        .q_pre_exec    = (char*)"/bin/q_pre",
+        .q_post_exec   = (char*)"/bin/q_post",
+        .job_pre_exec  = (char*)"/bin/job_pre",
+        .job_post_exec = (char*)"/bin/job_post",
+    };
+
+    add_worker(&list, pid, WORKER_RUNNING, jobid, 1, &startinfo);
+    TEST_ASSERT_NOT_NULL(list);
+    remove_worker(&list, pid);
+    TEST_ASSERT_NULL(list);
+}
+#endif
+
+static void test_remove_worker_frees_every_startinfo_copy(void)
+{
+#ifdef __SANITIZE_ADDRESS__
+    /* first round trip settles any lazy allocation (logging etc.) */
+    add_remove_full_startinfo_worker(4101, 91001);
+
+    size_t before = __sanitizer_get_current_allocated_bytes();
+    add_remove_full_startinfo_worker(4102, 91002);
+    size_t after = __sanitizer_get_current_allocated_bytes();
+
+    TEST_ASSERT_EQUAL_UINT64((uint64_t)before, (uint64_t)after);
+#else
+    TEST_IGNORE_MESSAGE("needs AddressSanitizer's allocator statistics");
+#endif
+}
+
 /* ════════════════════════════════════════════════════════════════════════
  * main
  * ════════════════════════════════════════════════════════════════════════ */
@@ -391,6 +440,7 @@ int main(void)
     RUN_TEST(test_lookup_after_expiry_prunes_entry_permanently);
     RUN_TEST(test_reconnect_restarts_window_for_outcome_finished_before_outage);
     RUN_TEST(test_unhealthy_connection_suspends_expiry);
+    RUN_TEST(test_remove_worker_frees_every_startinfo_copy);
 
     return UNITY_END();
 }