diff --git a/extern/storage-sealing/fsm.go b/extern/storage-sealing/fsm.go
index ddfebad24..4842e6023 100644
--- a/extern/storage-sealing/fsm.go
+++ b/extern/storage-sealing/fsm.go
@@ -225,6 +225,8 @@ func (m *Sealing) plan(events []statemachine.Event, state *SectorInfo) (func(sta
 
 	*/
 
+	m.stats.updateSector(m.minerSector(state.SectorNumber), state.State)
+
 	switch state.State {
 	// Happy path
 	case Empty:
diff --git a/extern/storage-sealing/sealing.go b/extern/storage-sealing/sealing.go
index 7ae2e5163..3ae75e189 100644
--- a/extern/storage-sealing/sealing.go
+++ b/extern/storage-sealing/sealing.go
@@ -81,6 +81,8 @@ type Sealing struct {
 	upgradeLk sync.Mutex
 	toUpgrade map[abi.SectorNumber]struct{}
 
+	stats SectorStats
+
 	getConfig GetSealingConfigFunc
 }
 
@@ -268,6 +270,12 @@ func (m *Sealing) newDealSector() (abi.SectorNumber, error) {
 		return 0, xerrors.Errorf("getting config: %w", err)
 	}
 
+	if cfg.MaxSealingSectors > 0 {
+		if m.stats.curSealing() > cfg.MaxSealingSectors {
+			return 0, xerrors.Errorf("too many sectors sealing")
+		}
+	}
+
 	if cfg.MaxWaitDealsSectors > 0 {
 		// run in a loop because we have to drop the map lock here for a bit
 		tries := 0
@@ -353,6 +361,17 @@ func (m *Sealing) newDealSector() (abi.SectorNumber, error) {
 
 // newSectorCC accepts a slice of pieces with no deal (junk data)
 func (m *Sealing) newSectorCC(sid abi.SectorNumber, pieces []Piece) error {
+	cfg, err := m.getConfig()
+	if err != nil {
+		return xerrors.Errorf("getting config: %w", err)
+	}
+
+	if cfg.MaxSealingSectors > 0 {
+		if m.stats.curSealing() > cfg.MaxSealingSectors {
+			return xerrors.Errorf("too many sectors sealing (curSealing: %d, max: %d)", m.stats.curSealing(), cfg.MaxSealingSectors)
+		}
+	}
+
 	rt, err := ffiwrapper.SealProofTypeFromSectorSize(m.sealer.SectorSize())
 	if err != nil {
 		return xerrors.Errorf("bad sector size: %w", err)
diff --git a/extern/storage-sealing/sector_state.go b/extern/storage-sealing/sector_state.go
index f2801c9fc..2f57d83e8 100644
--- a/extern/storage-sealing/sector_state.go
+++ b/extern/storage-sealing/sector_state.go
@@ -36,3 +36,14 @@ const (
 	RemoveFailed SectorState = "RemoveFailed"
 	Removed      SectorState = "Removed"
 )
+
+func toStatState(st SectorState) statSectorState {
+	switch st {
+	case Empty, WaitDeals, Packing, PreCommit1, PreCommit2, PreCommitting, PreCommitWait, WaitSeed, Committing, CommitWait, FinalizeSector:
+		return sstSealing
+	case Proving, Removed, Removing:
+		return sstProving
+	}
+
+	return sstFailed
+}
diff --git a/extern/storage-sealing/stats.go b/extern/storage-sealing/stats.go
new file mode 100644
index 000000000..3d31a39ff
--- /dev/null
+++ b/extern/storage-sealing/stats.go
@@ -0,0 +1,45 @@
+package sealing
+
+import (
+	"sync"
+
+	"github.com/filecoin-project/specs-actors/actors/abi"
+)
+
+type statSectorState int
+const (
+	sstSealing statSectorState = iota
+	sstFailed
+	sstProving
+	nsst
+)
+
+type SectorStats struct {
+	lk sync.Mutex
+
+	bySector map[abi.SectorID]statSectorState
+	totals [nsst]uint64
+}
+
+func (ss *SectorStats) updateSector(id abi.SectorID, st SectorState) {
+	ss.lk.Lock()
+	defer ss.lk.Unlock()
+
+	oldst, found := ss.bySector[id]
+	if found {
+		ss.totals[oldst]--
+	}
+
+	sst := toStatState(st)
+	ss.bySector[id] = sst
+	ss.totals[sst]++
+}
+
+
+// return the number of sectors currently in the sealing pipeline
+func (ss *SectorStats) curSealing() uint64 {
+	ss.lk.Lock()
+	defer ss.lk.Unlock()
+
+	return ss.totals[sstSealing] + ss.totals[sstFailed]
+}