diff --git a/components/devtools/actor.rs b/components/devtools/actor.rs
index a2499ec467b..b0cd26e2468 100644
--- a/components/devtools/actor.rs
+++ b/components/devtools/actor.rs
@@ -44,6 +44,7 @@ impl Actor + Send {
     /// Returns some reference to the boxed value if it is of type `T`, or
     /// `None` if it isn't.
     #[inline]
+    #[allow(unsafe_code)]
     pub fn downcast_ref<T: Reflect + 'static>(&self) -> Option<&T> {
         if self.is::<T>() {
             unsafe {
@@ -61,6 +62,7 @@ impl Actor + Send {
     /// Returns some mutable reference to the boxed value if it is of type `T`, or
     /// `None` if it isn't.
     #[inline]
+    #[allow(unsafe_code)]
     pub fn downcast_mut<T: Reflect + 'static>(&mut self) -> Option<&mut T> {
         if self.is::<T>() {
             unsafe {
diff --git a/components/devtools/lib.rs b/components/devtools/lib.rs
index d9335943b1e..046a6dbddc1 100644
--- a/components/devtools/lib.rs
+++ b/components/devtools/lib.rs
@@ -20,6 +20,7 @@
 #![plugin(serde_macros)]
 
 #![allow(non_snake_case)]
+#![deny(unsafe_code)]
 
 #[macro_use]
 extern crate log;
diff --git a/components/devtools_traits/lib.rs b/components/devtools_traits/lib.rs
index 65bbd238dd1..2013ec79c96 100644
--- a/components/devtools_traits/lib.rs
+++ b/components/devtools_traits/lib.rs
@@ -10,6 +10,8 @@
 #![crate_type = "rlib"]
 
 #![allow(non_snake_case)]
+#![deny(unsafe_code)]
+
 #![feature(custom_derive, plugin)]
 #![plugin(serde_macros)]