diff --git a/xrtpy/response/data/xrt_contam_on_ccd.geny b/xrtpy/response/data/xrt_contam_on_ccd.geny
index 8d7cbab65..e37bd8def 100644
Binary files a/xrtpy/response/data/xrt_contam_on_ccd.geny and b/xrtpy/response/data/xrt_contam_on_ccd.geny differ
diff --git a/xrtpy/response/effective_area.py b/xrtpy/response/effective_area.py
index 86ef309d4..537fe4098 100644
--- a/xrtpy/response/effective_area.py
+++ b/xrtpy/response/effective_area.py
@@ -3,8 +3,10 @@
     "effective_area",
 ]
 
+import datetime
 import math
 import numpy as np
+import os
 import scipy.io
 import sunpy.io.special
 import sunpy.time
@@ -39,6 +41,7 @@
 _ccd_contam_filename = (
     Path(__file__).parent.absolute() / "data" / "xrt_contam_on_ccd.geny"
 )
+
 _filter_contam_filename = (
     Path(__file__).parent.absolute() / "data" / "xrt_contam_on_filter.geny"
 )
@@ -97,33 +100,54 @@ def observation_date(self, date):
         self._observation_date = observation_date
 
     @property
-    def ccd_observation_date_to_seconds(self):
-        """Converting users observation date into seconds with respect to CCD contamination data. Used for interpolation."""
+    def xrt_contam_on_ccd_geny_update(self):
+        """Return a string of the last time the file was modified."""
+        modified_time = os.path.getmtime(_ccd_contam_filename)
+        modified_time_dt = datetime.datetime.fromtimestamp(modified_time)
 
-        ccd_observation_date_to_seconds = []
-        for time in _ccd_contamination_file_time:
-            t0 = _ccd_contamination_file_time[0]
-            dt = time - t0
-            ccd_observation_date_to_seconds.append(
-                (self.observation_date + timedelta(0, dt)).strftime("%S")
-            )
-
-        return ccd_observation_date_to_seconds[0]
+        return modified_time_dt.strftime("%Y/%m/%d")
 
     @property
     def ccd_data_dates_to_seconds(self):
         """Converting CCD data dates to datetimes."""
 
+        ccd_data_dates_dt = []
         ccd_data_dates_to_seconds = []
         for time in _ccd_contamination_file_time:
             t0 = _ccd_contamination_file_time[0]
             dt = time - t0
+            ccd_data_dates_dt.append(epoch + timedelta(0, dt))
             ccd_data_dates_to_seconds.append(
                 float((epoch + timedelta(0, dt)).strftime("%S"))
             )
 
+        if self.observation_date > ccd_data_dates_dt[-1]:
+            raise ValueError(
+                "No contamination data is presently available for "
+                f"{self.observation_date}.\n The latest available data is on "
+                f"{ccd_data_dates_dt[-1]}.\n Contamination data is "
+                "updated periodically. The last update was on "
+                f"{self.xrt_contam_on_ccd_geny_update}. If this is more "
+                "than one month ago, please raise an issue at: "
+                "https://github.com/HinodeXRT/xrtpy/issues/new"
+            )
         return ccd_data_dates_to_seconds
 
+    @property
+    def ccd_observation_date_to_seconds(self):
+        """Converting users observation date into seconds with
+        respect to CCD contamination data. Used for interpolation."""
+
+        ccd_observation_date_to_seconds = []
+        for time in _ccd_contamination_file_time:
+            t0 = _ccd_contamination_file_time[0]
+            dt = time - t0
+            ccd_observation_date_to_seconds.append(
+                (self.observation_date + timedelta(0, dt)).strftime("%S")
+            )
+
+        return ccd_observation_date_to_seconds[0]
+
     @property
     def filter_observation_date_to_seconds(self):
         """Converting users observation date into seconds with respect to filter contamination data. Used for interpolation."""
diff --git a/xrtpy/response/tests/test_effective_area.py b/xrtpy/response/tests/test_effective_area.py
index 78409a429..043e17784 100644
--- a/xrtpy/response/tests/test_effective_area.py
+++ b/xrtpy/response/tests/test_effective_area.py
@@ -46,6 +46,8 @@
     datetime(year=2015, month=9, day=22, hour=22, minute=1, second=1),
     datetime(year=2017, month=9, day=22, hour=22, minute=1, second=1),
     datetime(year=2019, month=9, day=23, hour=22, minute=1, second=1),
+    datetime(year=2020, month=9, day=23, hour=22, minute=1, second=1),
+    datetime(year=2021, month=9, day=23, hour=22, minute=1, second=1),
     datetime(year=2022, month=9, day=23, hour=22, minute=1, second=1),
 ]