diff --git a/.clippy.toml b/.clippy.toml
index d842e40..691a590 100644
--- a/.clippy.toml
+++ b/.clippy.toml
@@ -8,8 +8,6 @@ disallowed-macros = [
     { path = "std::dbg", reason = "it is okay to use during development, but please do not include it in main branch" },
 ]
 disallowed-methods = [
-    { path = "std::env::remove_var", reason = "this is not thread-safe and inherently unsafe; see <https://github.com/rust-lang/rust/issues/27970> for more" },
-    { path = "std::env::set_var", reason = "this is not thread-safe and inherently unsafe; see <https://github.com/rust-lang/rust/issues/27970> for more" },
 ]
 disallowed-types = [
 ]
diff --git a/Cargo.toml b/Cargo.toml
index eeb7602..b429611 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -42,6 +42,7 @@ members = [
 # This table is shared by projects under github.com/taiki-e.
 # It is not intended for manual editing.
 [workspace.lints.rust]
+deprecated_safe = "warn"
 improper_ctypes = "warn"
 improper_ctypes_definitions = "warn"
 non_ascii_idents = "warn"