diff --git a/drupal_queue.module b/drupal_queue.module
index 98617b8..cbb988d 100644
--- a/drupal_queue.module
+++ b/drupal_queue.module
@@ -38,7 +38,8 @@ function drupal_queue_cron_run() {
   drupal_queue_include();
 
   // Try to increase the maximum execution time if it is too low.
-  if (ini_get('max_execution_time') < 240 && !ini_get('safe_mode')) {
+  $max_execution = ini_get('max_execution_time');
+  if ($max_execution_time > 0 && $max_execution_time < 240 && !ini_get('safe_mode')) {
     set_time_limit(240);
   }