diff --git a/environments/access-med/environment.yml b/environments/access-med/environment.yml
index 86d0e5d..eca7854 100644
--- a/environments/access-med/environment.yml
+++ b/environments/access-med/environment.yml
@@ -33,7 +33,7 @@ dependencies:
 - netcdf4<=1.6.0 ### Workaround for https://github.com/pydata/xarray/issues/7079
 - mo_pack
 - nodejs>=20.0.0
-- numpy>=1.21, !=1.24.3  # severe masking bug
+- numpy>=1.21, !=1.24.3, <=1.23.5  # severe masking bug
 - pandas
 - scipy
 - h5py