diff --git a/crypto/internal.h b/crypto/internal.h
index fe4ed73..5574aab 100644
--- a/crypto/internal.h
+++ b/crypto/internal.h
@@ -334,7 +334,7 @@
 typedef uint32_t CRYPTO_once_t;
 #define CRYPTO_ONCE_INIT 0
 #elif defined(OPENSSL_WINDOWS)
-typedef LONG CRYPTO_once_t;
+typedef volatile LONG CRYPTO_once_t;
 #define CRYPTO_ONCE_INIT 0
 #else
 typedef pthread_once_t CRYPTO_once_t;
diff --git a/crypto/thread_win.c b/crypto/thread_win.c
index 5efd8be..e1b3a54 100644
--- a/crypto/thread_win.c
+++ b/crypto/thread_win.c
@@ -31,9 +31,7 @@
 OPENSSL_COMPILE_ASSERT(sizeof(CRYPTO_MUTEX) >= sizeof(CRITICAL_SECTION),
                        CRYPTO_MUTEX_too_small);
 
-static void run_once(CRYPTO_once_t *in_once, void (*init)(void *), void *arg) {
-  volatile LONG *once = in_once;
-
+static void run_once(CRYPTO_once_t *once, void (*init)(void *), void *arg) {
   /* Values must be aligned. */
   assert((((uintptr_t) once) & 3) == 0);