diff --git a/core/src/main/java/com/boydti/fawe/command/AnvilCommands.java b/core/src/main/java/com/boydti/fawe/command/AnvilCommands.java
index 921167f7..f1437efb 100644
--- a/core/src/main/java/com/boydti/fawe/command/AnvilCommands.java
+++ b/core/src/main/java/com/boydti/fawe/command/AnvilCommands.java
@@ -68,6 +68,12 @@ public class AnvilCommands {
      */
     @Deprecated
     public static <G, T extends MCAFilter<G>> T runWithWorld(Player player, String folder, T filter, boolean force) {
+        return runWithWorld(player, folder, filter, force, false);
+    }
+
+
+    @Deprecated
+    public static <G, T extends MCAFilter<G>> T runWithWorld(Player player, String folder, T filter, boolean force, boolean unsafe) {
         boolean copy = false;
         if (FaweAPI.getWorld(folder) != null) {
             if (!force) {
@@ -78,7 +84,7 @@ public class AnvilCommands {
         }
         FaweQueue defaultQueue = SetQueue.IMP.getNewQueue(folder, true, false);
         MCAQueue queue = new MCAQueue(defaultQueue);
-        if (copy) {
+        if (copy && !unsafe) {
             return queue.filterCopy(filter, RegionWrapper.GLOBAL());
         } else {
             return queue.filterWorld(filter);
@@ -284,9 +290,21 @@ public class AnvilCommands {
             desc = "Trim all air in the world"
     )
     @CommandPermissions("worldedit.anvil.trimallair")
-    public void trimAllAir(Player player, String folder) throws WorldEditException {
+    public void trimAllAir(Player player, String folder, @Switch('u') boolean unsafe) throws WorldEditException {
         TrimAirFilter filter = new TrimAirFilter();
-        TrimAirFilter result = runWithWorld(player, folder, filter, true);
+        TrimAirFilter result = runWithWorld(player, folder, filter, true, unsafe);
+        if (result != null) player.print(BBC.getPrefix() + BBC.VISITOR_BLOCK.format(result.getTotal()));
+    }
+
+
+    @Command(
+            aliases = {"debugfixair", },
+            desc = "debug"
+    )
+    @CommandPermissions("worldedit.anvil.debugfixair")
+    public void debugfixair(Player player, String folder) throws WorldEditException {
+        DebugFixAir filter = new DebugFixAir();
+        DebugFixAir result = runWithWorld(player, folder, filter, true, true);
         if (result != null) player.print(BBC.getPrefix() + BBC.VISITOR_BLOCK.format(result.getTotal()));
     }
 
diff --git a/core/src/main/java/com/boydti/fawe/jnbt/anvil/filters/DebugFixAir.java b/core/src/main/java/com/boydti/fawe/jnbt/anvil/filters/DebugFixAir.java
new file mode 100644
index 00000000..96ab3a19
--- /dev/null
+++ b/core/src/main/java/com/boydti/fawe/jnbt/anvil/filters/DebugFixAir.java
@@ -0,0 +1,82 @@
+package com.boydti.fawe.jnbt.anvil.filters;
+
+import com.boydti.fawe.Fawe;
+import com.boydti.fawe.jnbt.anvil.MCAChunk;
+import com.boydti.fawe.jnbt.anvil.MCAFile;
+import com.boydti.fawe.jnbt.anvil.MCAFilterCounter;
+import com.boydti.fawe.object.RunnableVal;
+import com.boydti.fawe.object.number.MutableLong;
+import com.sk89q.worldedit.blocks.BlockID;
+
+public class DebugFixAir extends MCAFilterCounter {
+    @Override
+    public MCAChunk applyChunk(MCAChunk chunk, MutableLong cache) {
+        none:
+        {
+            some:
+            {
+                for (int layer = 0; layer < chunk.ids.length; layer++) {
+                    byte[] idLayer = chunk.ids[layer];
+                    if (idLayer == null) continue;
+                    for (int i = 0; i < 4096; i++) {
+                        if (idLayer[i] != 0) {
+                            if (layer != 0) break some;
+                            break none;
+                        }
+                    }
+                    { // Possibly dead code depending on the generator
+                        chunk.ids[layer] = null;
+                        chunk.data[layer] = null;
+                        chunk.setModified();
+                    }
+                }
+                cache.add(Character.MAX_VALUE);
+                chunk.setDeleted(true);
+                return null;
+            }
+            return null;
+        }
+
+        for (int i = 0; i < 5; i++) {
+            if (chunk.ids[i] == null) return null;
+        }
+        // layer 0
+        boolean modified = false;
+        byte[] ids0 = chunk.ids[0];
+        for (int i = 0; i < 256; i++) {
+            if (ids0[i] == 0) {
+                if (!modified) {
+                    modified = true;
+                }
+                for (int layer = 0; layer < 4; layer++) {
+                    byte[] arr = chunk.ids[layer];
+                    for (int y = i; y < 4096; y += 256) {
+                        arr[y] = BlockID.DIRT;
+                    }
+                }
+                ids0[i] = BlockID.BEDROCK;
+                chunk.ids[4][i] = BlockID.GRASS;
+                cache.add(256);
+            }
+        }
+        if (modified) chunk.setModified();
+        return null;
+    }
+
+    @Override
+    public void finishFile(MCAFile file, MutableLong cache) {
+        Fawe.debug(" - apply " + file.getFile());
+        boolean[] deleteFile = { true };
+        file.forEachCachedChunk(new RunnableVal<MCAChunk>() {
+            @Override
+            public void run(MCAChunk value) {
+                if (!value.isDeleted()) {
+                    deleteFile[0] = false;
+                }
+            }
+        });
+        if (deleteFile[0]) {
+            file.setDeleted(true);
+        }
+    }
+}
diff --git a/core/src/main/java/com/boydti/fawe/jnbt/anvil/filters/TrimAirFilter.java b/core/src/main/java/com/boydti/fawe/jnbt/anvil/filters/TrimAirFilter.java
index 67aa4ad4..178db7ee 100644
--- a/core/src/main/java/com/boydti/fawe/jnbt/anvil/filters/TrimAirFilter.java
+++ b/core/src/main/java/com/boydti/fawe/jnbt/anvil/filters/TrimAirFilter.java
@@ -23,6 +23,7 @@ public class TrimAirFilter extends MCAFilterCounter {
                 chunk.setModified();
             }
         }
+        cache.add(Character.MAX_VALUE);
         chunk.setDeleted(true);
         return null;
     }