diff --git a/openmc/data/thermal.py b/openmc/data/thermal.py
index 9c30634d0a..d0adbc4fe7 100644
--- a/openmc/data/thermal.py
+++ b/openmc/data/thermal.py
@@ -29,14 +29,14 @@ from .thermal_angle_energy import (CoherentElasticAE, IncoherentElasticAE,
 
 _THERMAL_NAMES = {
     'c_Al27': ('al', 'al27', 'al-27'),
-    'c_Al_in_Sapphire': ('asap00',),
+    'c_Al_in_Sapphire': ('asap00', 'asap'),
     'c_Be': ('be', 'be-metal', 'be-met', 'be00'),
     'c_BeO': ('beo',),
     'c_Be_in_BeO': ('bebeo', 'be-beo', 'be-o', 'be/o', 'bbeo00'),
     'c_Be_in_Be2C': ('bebe2c',),
     'c_C6H6': ('benz', 'c6h6'),
     'c_C_in_SiC': ('csic', 'c-sic'),
-    'c_Ca_in_CaH2': ('cah', 'cah00'),
+    'c_Ca_in_CaH2': ('cah', 'cah00', 'cacah2'),
     'c_D_in_D2O': ('dd2o', 'd-d2o', 'hwtr', 'hw', 'dhw00'),
     'c_D_in_D2O_ice': ('dice',),
     'c_Fe56': ('fe', 'fe56', 'fe-56'),
@@ -51,20 +51,20 @@ _THERMAL_NAMES = {
     'c_H_in_H2O': ('hh2o', 'h-h2o', 'lwtr', 'lw', 'lw00'),
     'c_H_in_H2O_solid': ('hice', 'h-ice', 'ice00'),
     'c_H_in_C5O2H8': ('lucite', 'c5o2h8', 'h-luci'),
-    'c_H_in_Mesitylene': ('mesi00',),
-    'c_H_in_Toluene': ('tol00',),
+    'c_H_in_Mesitylene': ('mesi00', 'mesi'),
+    'c_H_in_Toluene': ('tol00', 'tol'),
     'c_H_in_YH2': ('hyh2', 'h-yh2'),
     'c_H_in_ZrH': ('hzrh', 'h-zrh', 'h-zr', 'h/zr', 'hzr', 'hzr00'),
     'c_Mg24': ('mg', 'mg24', 'mg00'),
-    'c_O_in_Sapphire': ('osap00',),
+    'c_O_in_Sapphire': ('osap00', 'osap'),
     'c_O_in_BeO': ('obeo', 'o-beo', 'o-be', 'o/be', 'obeo00'),
     'c_O_in_D2O': ('od2o', 'o-d2o', 'ohw00'),
     'c_O_in_H2O_ice': ('oice', 'o-ice'),
     'c_O_in_UO2': ('ouo2', 'o-uo2', 'o2-u', 'o2/u', 'ouo200'),
     'c_N_in_UN': ('n-un',),
-    'c_ortho_D': ('orthod', 'orthoD', 'dortho', 'od200'),
-    'c_ortho_H': ('orthoh', 'orthoH', 'hortho', 'oh200'),
-    'c_Si28': ('si00',),
+    'c_ortho_D': ('orthod', 'orthoD', 'dortho', 'od200', 'ortod'),
+    'c_ortho_H': ('orthoh', 'orthoH', 'hortho', 'oh200', 'ortoh'),
+    'c_Si28': ('si00', 'sili'),
     'c_Si_in_SiC': ('sisic', 'si-sic'),
     'c_SiO2_alpha': ('sio2', 'sio2a'),
     'c_SiO2_beta': ('sio2b',),
diff --git a/src/nuclide.cpp b/src/nuclide.cpp
index 59c6311672..d388ed4abc 100644
--- a/src/nuclide.cpp
+++ b/src/nuclide.cpp
@@ -237,6 +237,16 @@ Nuclide::Nuclide(hid_t group, const std::vector<double>& temperature)
     // section should be determined from a normal reaction cross section, we
     // need to get the index of the reaction.
     if (temps_to_read.size() > 0) {
+      // Make sure inelastic flags are consistent for different temperatures
+      for (int i = 0; i < urr_data_.size() - 1; ++i) {
+        if (urr_data_[i].inelastic_flag_ != urr_data_[i+1].inelastic_flag_) {
+          fatal_error(fmt::format("URR inelastic flag is not consistent for "
+            "multiple temperatures in nuclide {}. This most likely indicates "
+            "a problem in how the data was processed.", name_));
+        }
+      }
+
+
       if (urr_data_[0].inelastic_flag_ > 0) {
         for (int i = 0; i < reactions_.size(); i++) {
           if (reactions_[i]->mt_ == urr_data_[0].inelastic_flag_) {