diff --git a/include/openmc/hdf5_interface.h b/include/openmc/hdf5_interface.h
index c87abd84a1..d0474c8344 100644
--- a/include/openmc/hdf5_interface.h
+++ b/include/openmc/hdf5_interface.h
@@ -204,23 +204,19 @@ read_attribute(hid_t obj_id, const char* name, std::vector<std::string>& vec)
 
   // Allocate a C char array to get strings
   auto n = attribute_typesize(obj_id, name);
-  char** buffer = new char*[m];
-  for (int i = 0; i < m; i++) {
-    buffer[i] = new char[n];
-  }
+  char* buffer = new char[m*n];
 
   // Read char data in attribute
-  read_attr_string(obj_id, name, n, buffer[0]);
+  read_attr_string(obj_id, name, n, buffer);
 
   for (int i = 0; i < m; ++i) {
     // Determine proper length of string -- strlen doesn't work because
     // buffer[i] might not have any null characters
     std::size_t k = 0;
-    for (; k < n; ++k) if (buffer[i][k] == '\0') break;
+    for (; k < n; ++k) if (buffer[i*n + k] == '\0') break;
 
     // Create string based on (char*, size_t) constructor
-    vec.emplace_back(&buffer[i][0], k);
-    delete[] buffer[i];
+    vec.emplace_back(&buffer[i*n], k);
   }
   delete[] buffer;
 }