diff --git a/webrtc/call/flexfec_receive_stream_impl.cc b/webrtc/call/flexfec_receive_stream_impl.cc
index 16edadd803..ffb3455349 100644
--- a/webrtc/call/flexfec_receive_stream_impl.cc
+++ b/webrtc/call/flexfec_receive_stream_impl.cc
@@ -168,11 +168,8 @@ FlexfecReceiveStreamImpl::~FlexfecReceiveStreamImpl() {
 }
 
 void FlexfecReceiveStreamImpl::OnRtpPacket(const RtpPacketReceived& packet) {
-  {
-    rtc::CritScope cs(&crit_);
-    if (!started_)
-      return;
-  }
+  if (!started_.load())
+    return;
 
   if (!receiver_)
     return;
@@ -191,13 +188,11 @@ void FlexfecReceiveStreamImpl::OnRtpPacket(const RtpPacketReceived& packet) {
 }
 
 void FlexfecReceiveStreamImpl::Start() {
-  rtc::CritScope cs(&crit_);
-  started_ = true;
+  started_.store(true);
 }
 
 void FlexfecReceiveStreamImpl::Stop() {
-  rtc::CritScope cs(&crit_);
-  started_ = false;
+  started_.store(false);
 }
 
 // TODO(brandtr): Implement this member function when we have designed the
diff --git a/webrtc/call/flexfec_receive_stream_impl.h b/webrtc/call/flexfec_receive_stream_impl.h
index de5de4190c..d1c19ffc70 100644
--- a/webrtc/call/flexfec_receive_stream_impl.h
+++ b/webrtc/call/flexfec_receive_stream_impl.h
@@ -11,6 +11,7 @@
 #ifndef WEBRTC_CALL_FLEXFEC_RECEIVE_STREAM_IMPL_H_
 #define WEBRTC_CALL_FLEXFEC_RECEIVE_STREAM_IMPL_H_
 
+#include <atomic>
 #include <memory>
 
 #include "webrtc/call/flexfec_receive_stream.h"
@@ -52,8 +53,7 @@ class FlexfecReceiveStreamImpl : public FlexfecReceiveStream,
  private:
   // Config.
   const Config config_;
-  bool started_ GUARDED_BY(crit_);
-  rtc::CriticalSection crit_;
+  std::atomic<bool> started_;
 
   // Erasure code interfacing.
   const std::unique_ptr<FlexfecReceiver> receiver_;