diff --git a/src/main.zig b/src/main.zig
index 960a725..ffb9696 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -351,7 +351,9 @@ pub fn main() !void {
     // start GC loop on a plain thread — dp.gc() uses pool_io (Threaded) mutex
     // and pg.Pool. MUST NOT run as Evented fiber: Threaded futex on Evented
     // fiber dereferences NULL Thread.current() threadlocal → heap corruption.
-    const gc_thread = std.Thread.spawn(.{}, gcLoop, .{ &dp, pool_io }) catch |err| {
+    // sleeps via std.Thread.sleep (NOT io.sleep) — io.sleep on pool_io from
+    // a non-Io thread fails on the second tick and silently kills the loop.
+    const gc_thread = std.Thread.spawn(.{}, gcLoop, .{&dp}) catch |err| {
         log.err("failed to start GC thread: {s}", .{@errorName(err)});
         return err;
     };
@@ -462,15 +464,19 @@ fn runWsServer(server: *websocket.Server(broadcaster.Handler), listener: *Io.net
     server.runIo(listener, bc);
 }
 
-fn gcLoop(dp: *event_log_mod.DiskPersist, io: Io) void {
-    const gc_interval: u64 = 10 * 60; // 10 minutes in seconds
+fn gcLoop(dp: *event_log_mod.DiskPersist) void {
+    const gc_interval_s: u64 = 10 * 60; // 10 minutes
     while (!shutdown_flag.load(.acquire)) {
-        // sleep in small increments to check shutdown
-        var remaining: u64 = gc_interval;
-        while (remaining > 0 and !shutdown_flag.load(.acquire)) {
-            const chunk = @min(remaining, 1);
-            io.sleep(Io.Duration.fromSeconds(@intCast(chunk)), .awake) catch return;
-            remaining -= chunk;
+        // sleep in 1s ticks so shutdown is checked frequently. uses
+        // std.c.nanosleep directly — this is a plain OS thread, so calling
+        // io.sleep on pool_io would fail on the second tick and silently
+        // exit the loop via `catch return`. zig 0.16 has no std.Thread.sleep
+        // and std.posix.nanosleep was removed during the Io migration.
+        var elapsed: u64 = 0;
+        while (elapsed < gc_interval_s and !shutdown_flag.load(.acquire)) {
+            const ts: std.c.timespec = .{ .sec = 1, .nsec = 0 };
+            _ = std.c.nanosleep(&ts, null);
+            elapsed += 1;
         }
         if (shutdown_flag.load(.acquire)) return;