diff --git a/src/fof.c b/src/fof.c
index 58c9268d67ff5b20541e5c05999dfb01f3a4e17d..f51bf74914a12284bdc03b3e17c9ecefc985fd44 100644
--- a/src/fof.c
+++ b/src/fof.c
@@ -279,7 +279,7 @@ void fof_allocate(const struct space *s, const long long total_nr_DM_particles,
   } else {
 
     /* Safety check */
-    if (!(s->e->policy | engine_policy_cosmology))
+    if (!(s->e->policy & engine_policy_cosmology))
       error(
           "Attempting to run FoF on a simulation using cosmological "
           "information but cosmology was not initialised");