diff --git a/src/Symfony/Component/HttpKernel/Kernel.php b/src/Symfony/Component/HttpKernel/Kernel.php
index a30d5916f9ae6..2f0453031f2dd 100644
--- a/src/Symfony/Component/HttpKernel/Kernel.php
+++ b/src/Symfony/Component/HttpKernel/Kernel.php
@@ -120,7 +120,7 @@ public function boot()
 
             return;
         }
-        if ($this->debug && !isset($_SERVER['SHELL_VERBOSITY'])) {
+        if ($this->debug && !isset($_ENV['SHELL_VERBOSITY']) && !isset($_SERVER['SHELL_VERBOSITY'])) {
             putenv('SHELL_VERBOSITY=3');
             $_ENV['SHELL_VERBOSITY'] = 3;
             $_SERVER['SHELL_VERBOSITY'] = 3;