diff --git a/src/main/java/de/ellpeck/actuallyadditions/mod/tile/TileEntityLaserRelayEnergy.java b/src/main/java/de/ellpeck/actuallyadditions/mod/tile/TileEntityLaserRelayEnergy.java
index 2085346fd..718abc0d1 100644
--- a/src/main/java/de/ellpeck/actuallyadditions/mod/tile/TileEntityLaserRelayEnergy.java
+++ b/src/main/java/de/ellpeck/actuallyadditions/mod/tile/TileEntityLaserRelayEnergy.java
@@ -23,13 +23,13 @@ import net.minecraft.util.EnumFacing;
 import net.minecraft.util.math.BlockPos;
 
 import java.util.ArrayList;
-import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 
 public class TileEntityLaserRelayEnergy extends TileEntityLaserRelay implements IEnergyReceiver{
 
-    public final Map<EnumFacing, TileEntity> receiversAround = new HashMap<EnumFacing, TileEntity>();
+    public final ConcurrentHashMap<EnumFacing, TileEntity> receiversAround = new ConcurrentHashMap<EnumFacing, TileEntity>();
 
     public static final int CAP = 1000;
 
diff --git a/src/main/java/de/ellpeck/actuallyadditions/mod/tile/TileEntityLaserRelayItem.java b/src/main/java/de/ellpeck/actuallyadditions/mod/tile/TileEntityLaserRelayItem.java
index 8dcb1f6b7..99c7faa45 100644
--- a/src/main/java/de/ellpeck/actuallyadditions/mod/tile/TileEntityLaserRelayItem.java
+++ b/src/main/java/de/ellpeck/actuallyadditions/mod/tile/TileEntityLaserRelayItem.java
@@ -22,13 +22,13 @@ import net.minecraftforge.items.CapabilityItemHandler;
 import net.minecraftforge.items.IItemHandler;
 
 import java.util.ArrayList;
-import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 
 public class TileEntityLaserRelayItem extends TileEntityLaserRelay{
 
-    public final Map<BlockPos, IItemHandler> handlersAround = new HashMap<BlockPos, IItemHandler>();
+    public final Map<BlockPos, IItemHandler> handlersAround = new ConcurrentHashMap<BlockPos, IItemHandler>();
 
     public TileEntityLaserRelayItem(String name){
         super(name, true);