diff --git a/src/main/java/com/gmail/nossr50/util/blockmeta/chunkmeta/PrimitiveChunkStore.java b/src/main/java/com/gmail/nossr50/util/blockmeta/chunkmeta/PrimitiveChunkStore.java
index c12b34fbb..5ea231c74 100755
--- a/src/main/java/com/gmail/nossr50/util/blockmeta/chunkmeta/PrimitiveChunkStore.java
+++ b/src/main/java/com/gmail/nossr50/util/blockmeta/chunkmeta/PrimitiveChunkStore.java
@@ -56,7 +56,7 @@ public class PrimitiveChunkStore implements ChunkStore {
 
     @Override
     public void setTrue(int x, int y, int z) {
-        if (z > maxZ)
+        if (z > maxZ || z < 0)
             return;
         store[x][z][y] = true;
         dirty = true;
@@ -64,7 +64,7 @@ public class PrimitiveChunkStore implements ChunkStore {
 
     @Override
     public void setFalse(int x, int y, int z) {
-        if (z > maxZ)
+        if (z > maxZ || z < 0)
             return;
         store[x][z][y] = false;
         dirty = true;