diff --git a/rtiow/Cargo.lock b/rtiow/Cargo.lock
index 5c0b173..9df414c 100644
--- a/rtiow/Cargo.lock
+++ b/rtiow/Cargo.lock
@@ -1606,7 +1606,6 @@ dependencies = [
  "chrono 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "cpuprofiler 0.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "criterion 0.2.10 (registry+https://github.com/rust-lang/crates.io-index)",
- "crossbeam-channel 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "image 0.19.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
diff --git a/rtiow/Cargo.toml b/rtiow/Cargo.toml
index 467cafa..7ad00c9 100644
--- a/rtiow/Cargo.toml
+++ b/rtiow/Cargo.toml
@@ -13,7 +13,6 @@ actix-web = "0.7.8"
 askama = "0.7.1"
 chrono = "*"
 cpuprofiler = { version = "0.0.3", optional = true }
-crossbeam-channel = "0.3"
 image = "0.19.0"
 lazy_static = "1.1.0"
 log = "0.4.5"
diff --git a/rtiow/src/lib.rs b/rtiow/src/lib.rs
index 25d808c..2ffe432 100644
--- a/rtiow/src/lib.rs
+++ b/rtiow/src/lib.rs
@@ -20,7 +20,6 @@ pub mod texture;
 pub mod translate;
 pub mod vec3;
 
-extern crate crossbeam_channel;
 extern crate image;
 #[macro_use]
 extern crate log;
diff --git a/rtiow/src/renderer.rs b/rtiow/src/renderer.rs
index a1c7af0..b43d66e 100644
--- a/rtiow/src/renderer.rs
+++ b/rtiow/src/renderer.rs
@@ -6,9 +6,13 @@ use std::path::Path;
 use std::path::PathBuf;
 use std::str;
 use std::sync;
+use std::sync::mpsc::sync_channel;
+use std::sync::mpsc::Receiver;
+use std::sync::mpsc::SyncSender;
+use std::sync::Arc;
+use std::sync::Mutex;
 use std::thread;
 
-use crossbeam_channel as channel;
 use image;
 use image::RgbImage;
 use num_cpus;
@@ -156,7 +160,7 @@ pub fn opt_hash(opt: &Opt) -> String {
 }
 
 pub struct Scene {
-    pub world: Box<Hit>,
+    pub world: Box<dyn Hit>,
     pub camera: Camera,
     pub subsamples: usize,
     pub num_threads: Option<usize>,
@@ -171,7 +175,7 @@ pub struct Scene {
 // world.  If false, it is expected the scene has emissive light sources.
 fn color(
     r: Ray,
-    world: &Hit,
+    world: &dyn Hit,
     depth: usize,
     global_illumination: bool,
     env_map: &Option<EnvMap>,
@@ -255,19 +259,25 @@ fn render_pixel(scene: &Scene, x: usize, y: usize) -> Vec3 {
 fn render_worker(
     tid: usize,
     scene: &Scene,
-    input_chan: channel::Receiver<Request>,
-    output_chan: &channel::Sender<Response>,
+    input_chan: Arc<Mutex<Receiver<Request>>>,
+    output_chan: &SyncSender<Response>,
 ) {
-    for req in input_chan {
-        match req {
-            Request::Line { width, y } => {
-                let pixels = (0..width).map(|x| render_pixel(scene, x, y)).collect();
-                output_chan.send(Response::Line { width, y, pixels });
-            }
-            Request::Pixel { x, y } => {
-                let pixel = render_pixel(scene, x, y);
-                output_chan.send(Response::Pixel { x, y, pixel });
+    loop {
+        match input_chan.lock().unwrap().recv() {
+            Err(err) => {
+                info!("Shutting down render_worker {}: {}", tid, err);
+                return;
             }
+            Ok(req) => match req {
+                Request::Line { width, y } => {
+                    let pixels = (0..width).map(|x| render_pixel(scene, x, y)).collect();
+                    output_chan.send(Response::Line { width, y, pixels });
+                }
+                Request::Pixel { x, y } => {
+                    let pixel = render_pixel(scene, x, y);
+                    output_chan.send(Response::Pixel { x, y, pixel });
+                }
+            },
         }
     }
     trace!(target: "renderer", "Shutting down worker {}", tid);
@@ -275,10 +285,11 @@ fn render_worker(
 
 pub fn render(scene: Scene, output_dir: &Path) -> std::result::Result<(), std::io::Error> {
     let num_threads = scene.num_threads.unwrap_or_else(num_cpus::get);
-    let (pixel_req_tx, pixel_req_rx) = channel::bounded(2 * num_threads);
-    let (pixel_resp_tx, pixel_resp_rx) = channel::bounded(2 * num_threads);
+    let (pixel_req_tx, pixel_req_rx) = sync_channel(2 * num_threads);
+    let (pixel_resp_tx, pixel_resp_rx) = sync_channel(2 * num_threads);
 
-    let scene = sync::Arc::new(scene);
+    let scene = Arc::new(scene);
+    let pixel_req_rx = Arc::new(Mutex::new(pixel_req_rx));
     println!("Creating {} render threads", num_threads);
     for i in 0..num_threads {
         let s = sync::Arc::clone(&scene);
@@ -293,8 +304,8 @@ pub fn render(scene: Scene, output_dir: &Path) -> std::result::Result<(), std::i
 
     let (w, h) = (scene.width, scene.height);
     thread::spawn(move || {
-        let batch_by_line = true;
-        if batch_by_line {
+        let batch_line_requests = true;
+        if batch_line_requests {
             for y in 0..h {
                 pixel_req_tx.send(Request::Line { width: w, y });
             }