Apache keeps restarting with DaemonTools

I've installed DaemonTools, created /service/apache

and wrote a very simple run with the lines:

#!/bin/sh
exec /path/to/httpd/binary/httpd

the line "exec /path/httpd" works from the command line and I get httpd in the background when I check with ps and also port 80 is bound to with netstat.

However, when I use this run script with daemontools service, the process restarts every second such that it never appears in the ps list. It's pid keeps changing indicating a constantly respawning process.

Any idea why this is?