diff --git a/src/workerd/api/node/zlib-util.c++ b/src/workerd/api/node/zlib-util.c++
index 01d58c47f9a..18585b285b8 100644
--- a/src/workerd/api/node/zlib-util.c++
+++ b/src/workerd/api/node/zlib-util.c++
@@ -108,7 +108,7 @@ kj::Maybe<CompressionError> ZlibContext::setDictionary() {
 }
 
 bool ZlibContext::initializeZlib() {
-  if (initialized.lockExclusive()) {
+  if (initialized) {
     return false;
   }
   switch (mode) {
@@ -134,7 +134,7 @@ bool ZlibContext::initializeZlib() {
   }
 
   setDictionary();
-  *initialized.lockExclusive() = true;
+  initialized = true;
   return true;
 }
 
@@ -284,7 +284,7 @@ kj::Maybe<CompressionError> ZlibContext::setParams(int _level, int _strategy) {
 }
 
 void ZlibContext::close() {
-  if (!initialized.lockExclusive()) {
+  if (!initialized) {
     dictionary.clear();
     mode = ZlibMode::NONE;
     return;
diff --git a/src/workerd/api/node/zlib-util.h b/src/workerd/api/node/zlib-util.h
index ce4239969df..ecf34a2aa37 100644
--- a/src/workerd/api/node/zlib-util.h
+++ b/src/workerd/api/node/zlib-util.h
@@ -10,7 +10,6 @@
 #include "zlib.h"
 #include <kj/array.h>
 #include <kj/compat/brotli.h>
-#include <kj/mutex.h>
 #include <kj/vector.h>
 
 #include <cstdlib>
@@ -142,7 +141,7 @@ class ZlibContext final {
     return {kj::str(message), kj::str(ZlibStrerror(err)), err};
   };
 
-  kj::MutexGuarded<bool> initialized{false};
+  bool initialized = false;
   ZlibMode mode = ZlibMode::NONE;
   int flush = Z_NO_FLUSH;
   int windowBits = 0;