diff --git a/pkgs/development/interpreters/dhall/build-dhall-url.nix b/pkgs/development/interpreters/dhall/build-dhall-url.nix
index 766fe3c1c2e3..9dcd885d25c3 100644
--- a/pkgs/development/interpreters/dhall/build-dhall-url.nix
+++ b/pkgs/development/interpreters/dhall/build-dhall-url.nix
@@ -76,7 +76,8 @@ let
    sourceFile = "source.dhall";
 
 in
-  runCommand name { } (''
+  runCommand name { impureEnvVars = lib.fetchers.proxyImpureEnvVars; }
+ (''
     set -eu
 
     mkdir -p ${cacheDhall} $out/${cacheDhall}