diff --git a/ethcore/src/engines/tendermint/mod.rs b/ethcore/src/engines/tendermint/mod.rs
index 8bbed8c84..02cd114b5 100644
--- a/ethcore/src/engines/tendermint/mod.rs
+++ b/ethcore/src/engines/tendermint/mod.rs
@@ -78,14 +78,14 @@ pub struct Tendermint {
proposer_nonce: AtomicUsize,
/// Vote accumulator.
votes: VoteCollector,
- /// Proposed block held until seal is gathered.
- proposed_block: Mutex