diff --git a/pom.xml b/pom.xml
index 0323d96..74e422a 100644
--- a/pom.xml
+++ b/pom.xml
@@ -6,7 +6,7 @@
 
     <groupId>org.ohnlp.medtagger</groupId>
     <artifactId>medtagger</artifactId>
-    <version>1.0.35</version>
+    <version>1.0.36</version>
     <description>The MedTagger biomedical information extraction pipeline</description>
 
 
diff --git a/src/main/java/org/ohnlp/medtagger/backbone/MedTaggerBackboneTransform.java b/src/main/java/org/ohnlp/medtagger/backbone/MedTaggerBackboneTransform.java
index 01a7130..2b1c9e3 100644
--- a/src/main/java/org/ohnlp/medtagger/backbone/MedTaggerBackboneTransform.java
+++ b/src/main/java/org/ohnlp/medtagger/backbone/MedTaggerBackboneTransform.java
@@ -40,6 +40,8 @@
 import java.text.SimpleDateFormat;
 import java.util.*;
 import java.util.concurrent.*;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.locks.ReentrantLock;
 import java.util.stream.Collectors;
 
 import static org.apache.uima.fit.factory.AnalysisEngineFactory.createEngineDescription;
@@ -73,6 +75,8 @@ public PCollection<Row> expand(PCollection<Row> input) {
     }
 
     private static class MedTaggerPipelineFunction extends DoFn<Row, Row> {
+        private transient static final ReentrantLock INIT_MUTEX_LOCK = new ReentrantLock();
+
         private final String resourceFolder;
         private final String textField;
         private final RunMode mode;
@@ -92,77 +96,83 @@ public MedTaggerPipelineFunction(String textField, String resourceFolder, RunMod
 
         @Setup
         public void init() throws IOException, InvalidXMLException, URISyntaxException, ResourceInitializationException {
-            AggregateBuilder ae = new AggregateBuilder();
-            // Tokenization, Sentence Splitting, Section Detection, etc.
-            ae.add(createEngineDescription("desc.backbone.aes.PreConceptExtractionAE"));
-            // Add the appropriate NER/normalization component depending on run mode
-            URI uri = null;
-            switch (mode) {
-                case OHNLPTK_DEFINED: // Ruleset from a web service
-                    throw new UnsupportedOperationException("Remote Served IE Rulesets not yet implemented");
-                case STANDALONE:
-                case STANDALONE_IE_ONLY: {
-                    uri = MedTaggerPipelineFunction.class.getResource("/resources/" + this.resourceFolder).toURI();
-                    Map<String, String> env = new HashMap<>();
-                    env.put("create", "true");
-                    try {
-                        // Ensure it is created, ignore if not
-                        FileSystem fs = FileSystems.newFileSystem(uri, env);
-                    } catch (FileSystemAlreadyExistsException ignored) {
-                    }
-                    ae.add(createEngineDescription("org.ohnlp.medtagger.ie.aes.MedTaggerIEAnnotatorAE", "Resource_dir", uri.toString()));
-                    break;
-                }
-                case STANDALONE_DICT_ONLY: {
-                    uri = MedTaggerPipelineFunction.class.getResource("/resources/" + this.resourceFolder).toURI();
-                    Map<String, String> env = new HashMap<>();
-                    env.put("create", "true");
-                    try {
-                        // Ensure it is created, ignore if not
-                        FileSystem fs = FileSystems.newFileSystem(uri, env);
-                    } catch (FileSystemAlreadyExistsException ignored) {
+            try {
+                INIT_MUTEX_LOCK.lock();
+                AggregateBuilder ae = new AggregateBuilder();
+                // Tokenization, Sentence Splitting, Section Detection, etc.
+                ae.add(createEngineDescription("desc.backbone.aes.PreConceptExtractionAE"));
+                // Add the appropriate NER/normalization component depending on run mode
+                URI uri = null;
+                switch (mode) {
+                    case OHNLPTK_DEFINED: // Ruleset from a web service
+                        throw new UnsupportedOperationException("Remote Served IE Rulesets not yet implemented");
+                    case STANDALONE:
+                    case STANDALONE_IE_ONLY: {
+                        uri = MedTaggerPipelineFunction.class.getResource("/resources/" + this.resourceFolder).toURI();
+                        Map<String, String> env = new HashMap<>();
+                        env.put("create", "true");
+                        try {
+                            // Ensure it is created, ignore if not
+                            FileSystem fs = FileSystems.newFileSystem(uri, env);
+                        } catch (FileSystemAlreadyExistsException ignored) {
+                        }
+                        ae.add(createEngineDescription("org.ohnlp.medtagger.ie.aes.MedTaggerIEAnnotatorAE", "Resource_dir", uri.toString()));
+                        break;
                     }
-                    ae.add(createEngineDescription(AhoCorasickLookupAnnotator.class, "dict_file", uri.toString()));
-                    break;
-                }
-                case STANDALONE_DICT_AND_IE: {
-                    String[] parsed = this.resourceFolder.split("\\|");
-                    uri = MedTaggerPipelineFunction.class.getResource("/resources/" + parsed[0]).toURI();
-                    URI dictURI = null;
-                    if (parsed.length > 1) {
-                        dictURI = MedTaggerPipelineFunction.class.getResource("/resources/" + parsed[1]).toURI();
+                    case STANDALONE_DICT_ONLY: {
+                        uri = MedTaggerPipelineFunction.class.getResource("/resources/" + this.resourceFolder).toURI();
+                        Map<String, String> env = new HashMap<>();
+                        env.put("create", "true");
+                        try {
+                            // Ensure it is created, ignore if not
+                            FileSystem fs = FileSystems.newFileSystem(uri, env);
+                        } catch (FileSystemAlreadyExistsException ignored) {
+                        }
+                        ae.add(createEngineDescription(AhoCorasickLookupAnnotator.class, "dict_file", uri.toString()));
+                        break;
                     }
-                    Map<String, String> env = new HashMap<>();
-                    env.put("create", "true");
-                    try {
-                        // Ensure it is created, ignore if not
-                        FileSystem fs = FileSystems.newFileSystem(uri, env);
-                    } catch (FileSystemAlreadyExistsException ignored) {
+                    case STANDALONE_DICT_AND_IE: {
+                        String[] parsed = this.resourceFolder.split("\\|");
+                        uri = MedTaggerPipelineFunction.class.getResource("/resources/" + parsed[0]).toURI();
+                        URI dictURI = null;
+                        if (parsed.length > 1) {
+                            dictURI = MedTaggerPipelineFunction.class.getResource("/resources/" + parsed[1]).toURI();
+                        }
+                        Map<String, String> env = new HashMap<>();
+                        env.put("create", "true");
+                        try {
+                            // Ensure it is created, ignore if not
+                            FileSystem fs = FileSystems.newFileSystem(uri, env);
+                        } catch (FileSystemAlreadyExistsException ignored) {
+                        }
+                        ae.add(createEngineDescription("org.ohnlp.medtagger.ie.aes.MedTaggerIEAnnotatorAE", "Resource_dir", uri.toString()));
+                        if (dictURI != null) {
+                            ae.add(createEngineDescription("desc.backbone.aes.MedTaggerDictionaryLookupAE", "dict_file", dictURI.toString()));
+                        } else {
+                            ae.add(createEngineDescription("desc.backbone.aes.MedTaggerDictionaryLookupAE"));
+                        }
+                        break;
                     }
-                    ae.add(createEngineDescription("org.ohnlp.medtagger.ie.aes.MedTaggerIEAnnotatorAE", "Resource_dir", uri.toString()));
-                    if (dictURI != null) {
-                        ae.add(createEngineDescription("desc.backbone.aes.MedTaggerDictionaryLookupAE", "dict_file", dictURI.toString()));
-                    } else {
+                    case GENERAL_CLINICAL:
                         ae.add(createEngineDescription("desc.backbone.aes.MedTaggerDictionaryLookupAE"));
-                    }
-                    break;
+                        break;
+                }
+
+                // Add Context handling
+                if (uri != null) {
+                    ae.add(AnalysisEngineFactory.createEngineDescription(RuleContextAnnotator.class, "context_ruleset", uri.toString()));
+                } else {
+                    ae.add(AnalysisEngineFactory.createEngineDescription(RuleContextAnnotator.class));
                 }
-                case GENERAL_CLINICAL:
-                    ae.add(createEngineDescription("desc.backbone.aes.MedTaggerDictionaryLookupAE"));
-                    break;
-            }
 
-            // Add Context handling
-            if (uri != null) {
-                ae.add(AnalysisEngineFactory.createEngineDescription(RuleContextAnnotator.class, "context_ruleset", uri.toString()));
-            } else {
-                ae.add(AnalysisEngineFactory.createEngineDescription(RuleContextAnnotator.class));
+                this.resMgr = ResourceManagerFactory.newResourceManager();
+                this.aae = UIMAFramework.produceAnalysisEngine(ae.createAggregateDescription(), resMgr, null);
+                this.cas = CasCreationUtils.createCas(Collections.singletonList(aae.getMetaData()),
+                        null, resMgr);
+            } finally {
+                INIT_MUTEX_LOCK.unlock();
             }
 
-            this.resMgr = ResourceManagerFactory.newResourceManager();
-            this.aae = UIMAFramework.produceAnalysisEngine(ae.createAggregateDescription(), resMgr, null);
-            this.cas = CasCreationUtils.createCas(Collections.singletonList(aae.getMetaData()),
-                    null, resMgr);
         }
 
         @ProcessElement