diff --git a/src/errors.rs b/src/errors.rs
index 3194737..b66fae0 100644
--- a/src/errors.rs
+++ b/src/errors.rs
@@ -45,9 +45,6 @@ pub(crate) enum InternalError {
     PrehashedContextLengthError,
 }
 
-unsafe impl Send for InternalError {}
-unsafe impl Sync for InternalError {}
-
 impl Display for InternalError {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match *self {