diff --git a/addons/misra-test.c b/addons/misra-test.c
index cbc3f112e..256200dd5 100644
--- a/addons/misra-test.c
+++ b/addons/misra-test.c
@@ -210,5 +210,14 @@ void misra_21_3() {
 }
 
 void misra_21_7() {
+  atof(str); // 21.7
   atoi(str); // 21.7
+  atol(str); // 21.7
+  atoll(str); // 21.7
+}
+
+void misra_21_8() {
+  abort(); // 21.8
+  getenv("foo"); // 21.8
+  system(""); // 21.8
 }
diff --git a/addons/misra.py b/addons/misra.py
index af321edc2..fb414b6d3 100644
--- a/addons/misra.py
+++ b/addons/misra.py
@@ -674,6 +674,11 @@ def misra_21_7(data):
         if (token.str in ['atof', 'atoi', 'atol', 'atoll']) and token.next and token.next.str == '(':
             reportError(token, 21, 7)
 
+def misra_21_8(data):
+    for token in data.tokenlist:
+        if (token.str in ['abort', 'getenv', 'system']) and token.next and token.next.str == '(':
+            reportError(token, 21, 8)
+
 if '-verify' in sys.argv[1:]:
     VERIFY = True
 
@@ -750,6 +755,7 @@ for arg in sys.argv[1:]:
             misra_21_4(data.rawTokens)
             misra_21_5(data.rawTokens)
         misra_21_7(cfg)
+        misra_21_8(cfg)
 
     if VERIFY:
         for expected in VERIFY_EXPECTED: