diff --git a/svgnest.js b/svgnest.js
index 187356ad..7ef8d8e8 100644
--- a/svgnest.js
+++ b/svgnest.js
@@ -42,6 +42,7 @@
 		var best = null;
 		var workerTimer = null;
 		var progress = 0;
+		var activeWorkers = []; // Track active workers
 		
 		this.parsesvg = function(svgstring){
 			// reset if in progress
@@ -338,6 +339,9 @@
 				evalPath: 'util/eval.js'
 			});
 			
+			// Track this worker
+			activeWorkers.push(p);
+			
 			p.require('matrix.js');
 			p.require('geometryutil.js');
 			p.require('placementworker.js');
@@ -541,6 +545,9 @@
 					evalPath: 'util/eval.js'
 				});
 				
+				// Track this worker too
+				activeWorkers.push(p2);
+				
 				p2.require('json.js');
 				p2.require('clipper.js');
 				p2.require('matrix.js');
@@ -582,11 +589,25 @@
 						displayCallback();
 					}
 					self.working = false;
+					
+					// Remove completed workers from tracking
+					var index = activeWorkers.indexOf(p);
+					if (index > -1) activeWorkers.splice(index, 1);
+					index = activeWorkers.indexOf(p2);
+					if (index > -1) activeWorkers.splice(index, 1);
 				}, function (err) {
 					console.log(err);
+					// Remove failed workers from tracking
+					var index = activeWorkers.indexOf(p);
+					if (index > -1) activeWorkers.splice(index, 1);
+					index = activeWorkers.indexOf(p2);
+					if (index > -1) activeWorkers.splice(index, 1);
 				});
 			}, function (err) {
 				console.log(err);
+				// Remove failed worker from tracking
+				var index = activeWorkers.indexOf(p);
+				if (index > -1) activeWorkers.splice(index, 1);
 			});
 		}
 		
@@ -813,7 +834,23 @@
 			this.working = false;
 			if(workerTimer){
 				clearInterval(workerTimer);
+				workerTimer = null;
+			}
+			
+			// Terminate all active workers
+			for(var i = 0; i < activeWorkers.length; i++){
+				try {
+					if(activeWorkers[i] && typeof activeWorkers[i].kill === 'function'){
+						activeWorkers[i].kill();
+					}
+				} catch(e) {
+					// Ignore errors when terminating workers
+					console.log('Error terminating worker:', e);
+				}
 			}
+			
+			// Clear the active workers array
+			activeWorkers = [];
 		};
 	}