diff --git a/src/ace.F90 b/src/ace.F90
index e3327b2da5..68302b16fb 100644
--- a/src/ace.F90
+++ b/src/ace.F90
@@ -967,24 +967,23 @@ contains
       ! Continuous tabular distribution
       NR = int(XSS(lc + 1))
       NE = int(XSS(lc + 2 + 2*NR))
-      ! Before progressing, check to see if data set uses L(I) values
-      ! in a way inconsistent with the current form of the ACE Format Guide
-      ! (MCNP5 Manual, Vol 3)
       allocate(L(NE))
       L = int(XSS(lc + 3 + 2*NR + NE: lc + 3 + 2*NR + 2*NE - 1))
-      do i = 1,NE
-        ! Now check to see if L(i) is equal to any other entries
-        ! If so, then we must exit
-        if (count(L == L(i)) > 1) then
-          message = "Invalid usage of L(I) in ACE data; &
-                    &Consider using more recent data set."
-          call fatal_error()
-        end if
-      end do
-      deallocate(L)
+
       ! Continue with finding data length
       length = length + 2 + 2*NR + 2*NE
       do i = 1,NE
+        ! Some older data sets use the same LDAT for multiple Ein tables.
+        ! If this is the case, we should skip incrementing length when it is
+        ! not needed.
+        if (i < NE) then
+          if (L(i) == L(i + 1)) then
+            ! adjust location for this block
+            j = lc + 2 + 2*NR + NE + i
+            XSS(j) = XSS(j) - LOCC - lid
+            cycle
+          end if
+        end if
         ! determine length
         NP = int(XSS(lc + length + 2))
         length = length + 2 + 3*NP
@@ -993,6 +992,7 @@ contains
         j = lc + 2 + 2*NR + NE + i
         XSS(j) = XSS(j) - LOCC - lid
       end do
+      deallocate(L)
 
     case (5)
       ! General evaporation spectrum
@@ -1025,24 +1025,23 @@ contains
       ! Kalbach-Mann correlated scattering
       NR = int(XSS(lc + 1))
       NE = int(XSS(lc + 2 + 2*NR))
-      ! Before progressing, check to see if data set uses L(I) values
-      ! in a way inconsistent with the current form of the ACE Format Guide
-      ! (MCNP5 Manual, Vol 3)
       allocate(L(NE))
       L = int(XSS(lc + 3 + 2*NR + NE: lc + 3 + 2*NR + 2*NE - 1))
-      do i = 1,NE
-        ! Now check to see if L(i) is equal to any other entries
-        ! If so, then we must exit
-        if (count(L == L(i)) > 1) then
-          message = "Invalid usage of L(I) in ACE data; &
-                    &Consider using more recent data set."
-          call fatal_error()
-        end if
-      end do
-      deallocate(L)
+
       ! Continue with finding data length
       length = length + 2 + 2*NR + 2*NE
       do i = 1,NE
+        ! Some older data sets use the same LDAT for multiple Ein tables.
+        ! If this is the case, we should skip incrementing length when it is
+        ! not needed.
+        if (i < NE) then
+          if (L(i) == L(i + 1)) then
+            ! adjust location for this block
+            j = lc + 2 + 2*NR + NE + i
+            XSS(j) = XSS(j) - LOCC - lid
+            cycle
+          end if
+        end if
         NP = int(XSS(lc + length + 2))
         length = length + 2 + 5*NP
 
@@ -1050,29 +1049,30 @@ contains
         j = lc + 2 + 2*NR + NE + i
         XSS(j) = XSS(j) - LOCC - lid
       end do
+      deallocate(L)
 
     case (61)
       ! Correlated energy and angle distribution
       NR = int(XSS(lc + 1))
       NE = int(XSS(lc + 2 + 2*NR))
-      ! Before progressing, check to see if data set uses L(I) values
-      ! in a way inconsistent with the current form of the ACE Format Guide
-      ! (MCNP5 Manual, Vol 3)
       allocate(L(NE))
       L = int(XSS(lc + 3 + 2*NR + NE: lc + 3 + 2*NR + 2*NE - 1))
-      do i = 1,NE
-        ! Now check to see if L(i) is equal to any other entries
-        ! If so, then we must exit
-        if (count(L == L(i)) > 1) then
-          message = "Invalid usage of L(I) in ACE data; &
-                    &Consider using more recent data set."
-          call fatal_error()
-        end if
-      end do
-      deallocate(L)
+
       ! Continue with finding data length
       length = length + 2 + 2*NR + 2*NE
       do i = 1,NE
+        ! Some older data sets use the same LDAT for multiple Ein tables.
+        ! If this is the case, we should skip incrementing length when it is
+        ! not needed.
+        if (i < NE) then
+          if (L(i) == L(i + 1)) then
+            ! adjust locators for energy distribution
+            j = lc + 2 + 2*NR + NE + i
+            XSS(j) = XSS(j) - LOCC - lid
+            cycle
+          end if
+        end if
+
         ! outgoing energy distribution
         NP = int(XSS(lc + length + 2))
 
@@ -1094,7 +1094,7 @@ contains
         j = lc + 2 + 2*NR + NE + i
         XSS(j) = XSS(j) - LOCC - lid
       end do
-
+      deallocate(L)
     case (66)
       ! N-body phase space distribution
       length = 2
@@ -1108,15 +1108,7 @@ contains
       ! (MCNP5 Manual, Vol 3)
       allocate(L(NE))
       L = int(XSS(lc + 3 + 2*NR + NE: lc + 3 + 2*NR + 2*NE - 1))
-      do i = 1,NE
-        ! Now check to see if L(i) is equal to any other entries
-        ! If so, then we must exit
-        if (count(L == L(i)) > 1) then
-          message = "Invalid usage of L(I) in ACE data; &
-                    &Consider using more recent data set."
-          call fatal_error()
-        end if
-      end do
+      ! Don't currently do anything with L
       deallocate(L)
       ! Continue with finding data length
       NMU = int(XSS(lc + 4 + 2*NR + 2*NE))