diff --git a/src/populace_dynamics/data/sipp_jobs.py b/src/populace_dynamics/data/sipp_jobs.py
index 84076423..c722c9e5 100644
--- a/src/populace_dynamics/data/sipp_jobs.py
+++ b/src/populace_dynamics/data/sipp_jobs.py
@@ -379,12 +379,24 @@ def read_sipp_job_months(
             active & ~no_establishment,
             _EMPSIZE_CODES,
         )
-        bad_size = raw[f"EJB{n}_EMPSIZE"][
+        # A garbage *string* on a no-establishment slot would coerce
+        # to NaN and masquerade as the structural blank, so the raw
+        # cell is checked too: non-blank raw + NaN coercion refuses,
+        # keeping the loud-refusal posture symmetric with employer
+        # slots (review note on #206).
+        raw_size = raw[f"EJB{n}_EMPSIZE"]
+        raw_blank = raw_size.isna() | (raw_size.astype(str).str.strip() == "")
+        bad_size = raw_size[
             active
             & no_establishment
-            & empsize.notna()
-            & ~empsize.isin((_MISSING, _MISSING_ID))
-            & ~empsize.isin(sorted(_EMPSIZE_CODES))
+            & (
+                (
+                    empsize.notna()
+                    & ~empsize.isin((_MISSING, _MISSING_ID))
+                    & ~empsize.isin(sorted(_EMPSIZE_CODES))
+                )
+                | (empsize.isna() & ~raw_blank)
+            )
         ]
         if len(bad_size):
             raise _domain_error(year, f"EJB{n}_EMPSIZE", bad_size)
diff --git a/tests/data/test_sipp_jobs.py b/tests/data/test_sipp_jobs.py
index 0ed205e3..091bad1b 100644
--- a/tests/data/test_sipp_jobs.py
+++ b/tests/data/test_sipp_jobs.py
@@ -200,6 +200,26 @@ def test_corrupt_empsize_on_self_employment_refuses(self, tmp_path):
         with pytest.raises(ValueError, match="EJB1_EMPSIZE"):
             sipp_jobs.read_sipp_job_months(2023, path=path)
 
+    def test_garbage_string_empsize_on_se_slot_refuses(self, tmp_path):
+        # A non-numeric string coerces to NaN like a structural
+        # blank; the raw-cell guard keeps it a loud refusal on
+        # no-establishment slots too (post-merge review note).
+        # JBORSE 2 and 3 take the same no-establishment code path.
+        for jborse in (2, 3):
+            months = [
+                {
+                    "month": 1,
+                    "job1": {
+                        "JBORSE": jborse,
+                        "CLWRK": 8,
+                        "EMPSIZE": "GARBAGE",
+                    },
+                }
+            ]
+            path = _write_pu_file(tmp_path / f"j{jborse}", 2023, months)
+            with pytest.raises(ValueError, match="EJB1_EMPSIZE"):
+                sipp_jobs.read_sipp_job_months(2023, path=path)
+
     def test_corrupt_code_on_active_slot_refuses(self, tmp_path):
         # Only the -9/-999 sentinels excuse a non-domain value on an
         # active slot; an unparseable string or a blank must refuse
diff --git a/tests/tier_counts.json b/tests/tier_counts.json
index 01e321b2..9d39ce3d 100644
--- a/tests/tier_counts.json
+++ b/tests/tier_counts.json
@@ -1,7 +1,7 @@
 {
   "schema_version": 1,
   "counts": {
-    "unit": 650,
+    "unit": 651,
     "artifact": 1020,
     "integration_psid": 802,
     "reproduction_legacy": 520,