diff --git a/lualib-src/lua-bson.c b/lualib-src/lua-bson.c
index 808ca0f7..22dc64b2 100644
--- a/lualib-src/lua-bson.c
+++ b/lualib-src/lua-bson.c
@@ -1245,11 +1245,11 @@ typeclosure(lua_State *L) {
 }
 
 static uint8_t oid_header[5];
-static uint32_t oid_counter;
+static ATOM_ULONG oid_counter;
 
 static void
 init_oid_header() {
-	if (oid_counter) {
+	if (ATOM_LOAD(&oid_counter)) {
 		// already init
 		return;
 	}
@@ -1273,7 +1273,7 @@ init_oid_header() {
 	if (c == 0) {
 		c = 1;
 	}
-	oid_counter = c;
+	ATOM_STORE(&oid_counter, c);
 }
 
 static inline int