diff --git a/lvcnrpy/format/specs.py b/lvcnrpy/format/specs.py
index 26631ce93417a2955ffce00508e3761ca3016d15..f8710df33a72c459b451cc2f2b0b9173dd67887f 100644
--- a/lvcnrpy/format/specs.py
+++ b/lvcnrpy/format/specs.py
@@ -924,6 +924,9 @@ class PhaseSense(InterfieldSpec):
         # Determine sense from middle of pre-merger waveform
         phase = np.array([sim['phase_l2_m2/X'][:], sim['phase_l2_m2/Y'][:]])
         t0 = phase[0][0]*(3.0/4.0)
+        if t0 >= 0:
+            self.invalidMsg = "no (2,2) phase before 0M"
+            return err.InvalidInterfields(self)
         t1 = t0*(1.0/3.0)
         X = np.arange(t0, t1, 0.1)
         Y = IUS(*phase, k=5)(X)
diff --git a/lvcnrpy/test/test_lvcnrcheck.py b/lvcnrpy/test/test_lvcnrcheck.py
index 20a73357d7fd7758839b878facdbc88d0af31a2c..369b281c7ffb4e8f6d73065f29012ec494e9419f 100644
--- a/lvcnrpy/test/test_lvcnrcheck.py
+++ b/lvcnrpy/test/test_lvcnrcheck.py
@@ -1898,3 +1898,29 @@ class TestPhaseSense(TestInterfield):
         (output, returncode) = helper.lvcnrcheck(['-f', '3', self.f.name], returncode=True)
         assert output.strip() == self.output
         assert returncode == 1
+
+    def test_invalid_phase_zero_inspiral(self):
+        self.setOutput(
+            ('- [INVALID FIELDS] phase-sense '
+             '(Field dependencies are invalid)'))
+
+        nr = h5.File(self.f.name)
+        nr['phase_l2_m2']['X'][:] -= nr['phase_l2_m2']['X'][0]
+        nr.close()
+
+        (output, returncode) = helper.lvcnrcheck(['-f', '3', self.f.name], returncode=True)
+        assert output.strip() == self.output
+        assert returncode == 1
+
+    def test_invalid_phase_positive_inspiral(self):
+        self.setOutput(
+            ('- [INVALID FIELDS] phase-sense '
+             '(Field dependencies are invalid)'))
+
+        nr = h5.File(self.f.name)
+        nr['phase_l2_m2']['X'][:] += 10.0 - nr['phase_l2_m2']['X'][0]
+        nr.close()
+
+        (output, returncode) = helper.lvcnrcheck(['-f', '3', self.f.name], returncode=True)
+        assert output.strip() == self.output
+        assert returncode == 1