diff --git a/Cargo.toml b/Cargo.toml
index 89dba96..e6b054a 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -13,7 +13,7 @@ categories = ["asynchronous", "concurrency"]
 readme = "README.md"
 
 [dependencies]
-async-task = { path = "../async-task" }
+async-task = "4.0.0"
 concurrent-queue = "1.2.2"
 fastrand = "1.3.4"
 futures-lite = "1.0.0"
diff --git a/examples/priority.rs b/examples/priority.rs
index a30ad97..ef62324 100644
--- a/examples/priority.rs
+++ b/examples/priority.rs
@@ -18,23 +18,23 @@ enum Priority {
 /// An executor with task priorities.
 ///
 /// Tasks with lower priorities only get polled when there are no tasks with higher priorities.
-struct PriorityExecutor<'a> {
-    ex: [Executor<'a>; 3],
+struct PriorityExecutor {
+    ex: [Executor; 3],
 }
 
-impl<'a> PriorityExecutor<'a> {
+impl PriorityExecutor {
     /// Creates a new executor.
-    const fn new() -> PriorityExecutor<'a> {
+    const fn new() -> PriorityExecutor {
         PriorityExecutor {
             ex: [Executor::new(), Executor::new(), Executor::new()],
         }
     }
 
     /// Spawns a task with the given priority.
-    fn spawn<T: Send + 'a>(
+    fn spawn<T: Send + 'static>(
         &self,
         priority: Priority,
-        future: impl Future<Output = T> + Send + 'a,
+        future: impl Future<Output = T> + Send + 'static,
     ) -> Task<T> {
         self.ex[priority as usize].spawn(future)
     }
@@ -59,7 +59,7 @@ impl<'a> PriorityExecutor<'a> {
 }
 
 fn main() {
-    static EX: PriorityExecutor<'_> = PriorityExecutor::new();
+    static EX: PriorityExecutor = PriorityExecutor::new();
 
     // Spawn a thread running the executor forever.
     thread::spawn(|| future::block_on(EX.run()));
diff --git a/src/lib.rs b/src/lib.rs
index e963d3a..b3a7ae3 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -61,18 +61,14 @@ pub use async_task::Task;
 ///     }));
 /// ```
 #[derive(Debug)]
-pub struct Executor<'a> {
+pub struct Executor {
     state: once_cell::sync::OnceCell<Arc<State>>,
-    _marker: PhantomData<std::cell::UnsafeCell<&'a ()>>,
 }
 
-unsafe impl Send for Executor<'_> {}
-unsafe impl Sync for Executor<'_> {}
+impl UnwindSafe for Executor {}
+impl RefUnwindSafe for Executor {}
 
-impl UnwindSafe for Executor<'_> {}
-impl RefUnwindSafe for Executor<'_> {}
-
-impl<'a> Executor<'a> {
+impl Executor {
     /// Creates a new executor.
     ///
     /// # Examples
@@ -82,10 +78,9 @@ impl<'a> Executor<'a> {
     ///
     /// let ex = Executor::new();
     /// ```
-    pub const fn new() -> Executor<'a> {
+    pub const fn new() -> Executor {
         Executor {
             state: once_cell::sync::OnceCell::new(),
-            _marker: PhantomData,
         }
     }
 
@@ -102,8 +97,22 @@ impl<'a> Executor<'a> {
     ///     println!("Hello world");
     /// });
     /// ```
-    pub fn spawn<T: Send + 'a>(&self, future: impl Future<Output = T> + Send + 'a) -> Task<T> {
-        unsafe { self.spawn_unchecked(future) }
+    pub fn spawn<T: Send + 'static>(
+        &self,
+        future: impl Future<Output = T> + Send + 'static,
+    ) -> Task<T> {
+        let mut active = self.state().active.lock().unwrap();
+        let index = active.next_vacant();
+        let state = self.state().clone();
+        let future = async move {
+            let _guard = CallOnDrop(move || drop(state.active.lock().unwrap().remove(index)));
+            future.await
+        };
+
+        let (runnable, task) = async_task::spawn(future, self.schedule());
+        active.insert(runnable.waker());
+        runnable.schedule();
+        task
     }
 
     /// Attempts to run a task if at least one is scheduled.
@@ -211,24 +220,9 @@ impl<'a> Executor<'a> {
     fn state(&self) -> &Arc<State> {
         self.state.get_or_init(|| Arc::new(State::new()))
     }
-
-    unsafe fn spawn_unchecked<T>(&self, future: impl Future<Output = T>) -> Task<T> {
-        let mut active = self.state().active.lock().unwrap();
-        let index = active.next_vacant();
-        let state = self.state().clone();
-        let future = async move {
-            let _guard = CallOnDrop(move || drop(state.active.lock().unwrap().remove(index)));
-            future.await
-        };
-
-        let (runnable, task) = async_task::spawn_unchecked(future, self.schedule());
-        active.insert(runnable.waker());
-        runnable.schedule();
-        task
-    }
 }
 
-impl Drop for Executor<'_> {
+impl Drop for Executor {
     fn drop(&mut self) {
         if let Some(state) = self.state.get() {
             let mut active = state.active.lock().unwrap();
@@ -244,8 +238,8 @@ impl Drop for Executor<'_> {
     }
 }
 
-impl<'a> Default for Executor<'a> {
-    fn default() -> Executor<'a> {
+impl Default for Executor {
+    fn default() -> Executor {
         Executor::new()
     }
 }
@@ -267,18 +261,18 @@ impl<'a> Default for Executor<'a> {
 /// }));
 /// ```
 #[derive(Debug)]
-pub struct LocalExecutor<'a> {
+pub struct LocalExecutor {
     /// The inner executor.
-    inner: once_cell::unsync::OnceCell<Executor<'a>>,
+    inner: once_cell::unsync::OnceCell<Executor>,
 
     /// Make sure the type is `!Send` and `!Sync`.
     _marker: PhantomData<Rc<()>>,
 }
 
-impl UnwindSafe for LocalExecutor<'_> {}
-impl RefUnwindSafe for LocalExecutor<'_> {}
+impl UnwindSafe for LocalExecutor {}
+impl RefUnwindSafe for LocalExecutor {}
 
-impl<'a> LocalExecutor<'a> {
+impl LocalExecutor {
     /// Creates a single-threaded executor.
     ///
     /// # Examples
@@ -288,7 +282,7 @@ impl<'a> LocalExecutor<'a> {
     ///
     /// let local_ex = LocalExecutor::new();
     /// ```
-    pub const fn new() -> LocalExecutor<'a> {
+    pub const fn new() -> LocalExecutor {
         LocalExecutor {
             inner: once_cell::unsync::OnceCell::new(),
             _marker: PhantomData,
@@ -308,8 +302,19 @@ impl<'a> LocalExecutor<'a> {
     ///     println!("Hello world");
     /// });
     /// ```
-    pub fn spawn<T: 'a>(&self, future: impl Future<Output = T> + 'a) -> Task<T> {
-        unsafe { self.inner().spawn_unchecked(future) }
+    pub fn spawn<T: 'static>(&self, future: impl Future<Output = T> + 'static) -> Task<T> {
+        let mut active = self.inner().state().active.lock().unwrap();
+        let index = active.next_vacant();
+        let state = self.inner().state().clone();
+        let future = async move {
+            let _guard = CallOnDrop(move || drop(state.active.lock().unwrap().remove(index)));
+            future.await
+        };
+
+        let (runnable, task) = async_task::spawn_local(future, self.schedule());
+        active.insert(runnable.waker());
+        runnable.schedule();
+        task
     }
 
     /// Attempts to run a task if at least one is scheduled.
@@ -375,14 +380,24 @@ impl<'a> LocalExecutor<'a> {
         self.inner().run(future).await
     }
 
+    /// Returns a function that schedules a runnable task when it gets woken up.
+    fn schedule(&self) -> impl Fn(Runnable) + Send + Sync + 'static {
+        let state = self.inner().state().clone();
+
+        move |runnable| {
+            state.queue.push(runnable).unwrap();
+            state.notify();
+        }
+    }
+
     /// Returns a reference to the inner executor.
-    fn inner(&self) -> &Executor<'a> {
+    fn inner(&self) -> &Executor {
         self.inner.get_or_init(|| Executor::new())
     }
 }
 
-impl<'a> Default for LocalExecutor<'a> {
-    fn default() -> LocalExecutor<'a> {
+impl Default for LocalExecutor {
+    fn default() -> LocalExecutor {
         LocalExecutor::new()
     }
 }
@@ -402,6 +417,7 @@ struct State {
     /// A list of sleeping tickers.
     sleepers: Mutex<Sleepers>,
 
+    /// Currently active tasks.
     active: Mutex<Arena<Waker>>,
 }