diff --git a/src/atom.cpp b/src/atom.cpp
index d269fb8c2a..7b0ca8d0c6 100644
--- a/src/atom.cpp
+++ b/src/atom.cpp
@@ -1057,7 +1057,14 @@ void Atom::data_atoms(int n, char *buf, tagint id_offset, tagint mol_offset,
   next = strchr(buf,'\n');
   if (!next) error->all(FLERR, "Missing data in Atoms section of data file");
   *next = '\0';
-  int nwords = utils::trim_and_count_words(buf);
+  auto values = Tokenizer(buf).as_vector();
+  int nwords = 0;
+  for (std::size_t i = 0; i < values.size(); ++i) {
+    if (utils::strmatch(values[i], "^#")) {
+      nwords = i;
+      break;
+    }
+  }
   *next = '\n';
 
   if ((nwords != avec->size_data_atom) && (nwords != avec->size_data_atom + 3))
@@ -1135,10 +1142,12 @@ void Atom::data_atoms(int n, char *buf, tagint id_offset, tagint mol_offset,
     next = strchr(buf,'\n');
     if (!next) error->all(FLERR, "Missing data in Atoms section of data file");
     *next = '\0';
-    auto values = Tokenizer(utils::trim_comment(buf)).as_vector();
-    if (values.size() == 0) {
+    auto values = Tokenizer(buf).as_vector();
+    int nvalues = values.size();
+    if ((nvalues == 0) || (utils::strmatch(values[0],"^#.*")))  {
       // skip over empty or comment lines
-    } else if ((int)values.size() != nwords) {
+    } else if ((nvalues < nwords) ||
+               ((nvalues > nwords) && (!utils::strmatch(values[nwords],"^#")))) {
       error->all(FLERR, "Incorrect atom format in data file: {}", utils::trim(buf));
     } else {
       int imx = 0, imy = 0, imz = 0;
diff --git a/src/label_map.cpp b/src/label_map.cpp
index 72c20e56ac..4aeb4f29a1 100644
--- a/src/label_map.cpp
+++ b/src/label_map.cpp
@@ -138,9 +138,9 @@ void LabelMap::modify_lmap(int narg, char **arg)
     if ((itype < 1) || (itype > ntypes))
       error->all(FLERR, "Labelmap {} type {} must be within 1-{}", tlabel, itype, ntypes);
     std::string slabel(arg[iarg++]);
-    if (isdigit(slabel[0]))
-      error->all(FLERR, "Label {} for {} type {} must not start with a number", slabel, tlabel,
-                 itype);
+    if (isdigit(slabel[0]) || (slabel[0] == '#') || (slabel[0] == '*'))
+      error->all(FLERR, "Label {} for {} type {} must not start with a number, a '#', or a '*'",
+                 slabel, tlabel, itype);
     int found = search(slabel, (*labels_map));
     if ((found != -1) && (found != itype))
       error->all(FLERR, "The {} type label {} is already in use for type {}", tlabel, slabel,
diff --git a/unittest/commands/test_labelmap.cpp b/unittest/commands/test_labelmap.cpp
index 53a72a010f..15344b45bb 100644
--- a/unittest/commands/test_labelmap.cpp
+++ b/unittest/commands/test_labelmap.cpp
@@ -119,6 +119,10 @@ TEST_F(SetTest, NoBoxAtoms)
                  command("labelmap atom 5 C1"););
     TEST_FAILURE(".*ERROR: Label 1C for atom type 1 must not start with a number.*",
                  command("labelmap atom 1 1C"););
+    TEST_FAILURE(".*ERROR: Label #C for atom type 1 must not start with a number, a '#', or.*",
+                 command("labelmap atom 1 '#C'"););
+    TEST_FAILURE(".*ERROR: Label \\*C for atom type 1 must not start with a number, a '#', or.*",
+                 command("labelmap atom 1 *C"););
     TEST_FAILURE(".*ERROR: The atom type label N2 is already in use for type 2.*",
                  command("labelmap atom 1 N2"););