diff --git a/src/io/buffered.rs b/src/io/buffered.rs
index 001501dcaa..e0a5ab28da 100644
--- a/src/io/buffered.rs
+++ b/src/io/buffered.rs
@@ -10,6 +10,9 @@
 
 //! Buffering wrappers for I/O traits
 
+// TODO: set this for entire crate when possible
+#![deny(unsafe_op_in_unsafe_fn)]
+
 use core::{cmp, fmt};
 
 use crate::io::{
@@ -172,7 +175,7 @@ impl<R: Read> Read for BufReader<R> {
 
     // we can't skip unconditionally because of the large buffer case in read.
     unsafe fn initializer(&self) -> Initializer {
-        self.inner.initializer()
+        unsafe { self.inner.initializer() }
     }
 }
 
diff --git a/src/io/cursor.rs b/src/io/cursor.rs
index b2179bc14f..ff229bd0ce 100644
--- a/src/io/cursor.rs
+++ b/src/io/cursor.rs
@@ -8,6 +8,9 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+// TODO: set this for entire crate when possible
+#![deny(unsafe_op_in_unsafe_fn)]
+
 use core::cmp;
 
 use crate::io::{self, Error, ErrorKind, Initializer, SeekFrom, prelude::*};
@@ -253,7 +256,7 @@ where
 
     #[inline]
     unsafe fn initializer(&self) -> Initializer {
-        Initializer::nop()
+        unsafe { Initializer::nop() }
     }
 }
 
diff --git a/src/io/impls.rs b/src/io/impls.rs
index 80932844be..2168bc80ce 100644
--- a/src/io/impls.rs
+++ b/src/io/impls.rs
@@ -8,6 +8,9 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+// TODO: set this for entire crate when possible
+#![deny(unsafe_op_in_unsafe_fn)]
+
 use alloc::string::String;
 use core::{cmp, fmt, mem};
 
@@ -21,7 +24,7 @@ impl<'a, R: Read + ?Sized> Read for &'a mut R {
 
     #[inline]
     unsafe fn initializer(&self) -> Initializer {
-        (**self).initializer()
+        unsafe { (**self).initializer() }
     }
 
     #[cfg(feature = "alloc")]
@@ -100,7 +103,7 @@ impl<R: Read + ?Sized> Read for Box<R> {
 
     #[inline]
     unsafe fn initializer(&self) -> Initializer {
-        (**self).initializer()
+        unsafe { (**self).initializer() }
     }
 
     #[cfg(feature = "alloc")]
@@ -200,7 +203,7 @@ impl<'a> Read for &'a [u8] {
 
     #[inline]
     unsafe fn initializer(&self) -> Initializer {
-        Initializer::nop()
+        unsafe { Initializer::nop() }
     }
 
     #[inline]
diff --git a/src/io/mod.rs b/src/io/mod.rs
index 96c5813a17..ae4f50ab3a 100644
--- a/src/io/mod.rs
+++ b/src/io/mod.rs
@@ -267,6 +267,9 @@
 //! [`Result`]: ../result/enum.Result.html
 //! [`.unwrap()`]: ../result/enum.Result.html#method.unwrap
 
+// TODO: set this for entire crate when possible
+#![deny(unsafe_op_in_unsafe_fn)]
+
 pub mod buffered;
 pub mod cursor;
 pub mod error;
@@ -1393,11 +1396,11 @@ impl<T: Read, U: Read> Read for Chain<T, U> {
     }
 
     unsafe fn initializer(&self) -> Initializer {
-        let initializer = self.first.initializer();
+        let initializer = unsafe { self.first.initializer() };
         if initializer.should_initialize() {
             initializer
         } else {
-            self.second.initializer()
+            unsafe { self.second.initializer() }
         }
     }
 }
@@ -1586,7 +1589,7 @@ impl<T: Read> Read for Take<T> {
     }
 
     unsafe fn initializer(&self) -> Initializer {
-        self.inner.initializer()
+        unsafe { self.inner.initializer() }
     }
 
     fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize> {