diff --git a/src/shims/env.rs b/src/shims/env.rs
index 59fd16912a22..dfd1ef207d96 100644
--- a/src/shims/env.rs
+++ b/src/shims/env.rs
@@ -50,10 +50,10 @@ impl<'tcx> EnvVars<'tcx> {
 
         // Skip the loop entirely if we don't want to forward anything.
         if ecx.machine.communicate() || !forwarded_env_vars.is_empty() {
-            for (name, value) in env::vars() {
+            for (name, value) in env::vars_os() {
                 let forward = match ecx.machine.communicate() {
-                    true => !excluded_env_vars.contains(&name),
-                    false => forwarded_env_vars.contains(&name),
+                    true => !excluded_env_vars.iter().any(|v| v.as_str() == &name),
+                    false => forwarded_env_vars.iter().any(|v| v.as_str() == &name),
                 };
                 if forward {
                     let var_ptr = match target_os {