diff --git a/singularity/reditools2/env_reditools2.yml b/singularity/reditools2/env_reditools2.yml
index b832d8c..b62bc9f 100644
--- a/singularity/reditools2/env_reditools2.yml
+++ b/singularity/reditools2/env_reditools2.yml
@@ -10,4 +10,5 @@ dependencies:
   - python_abi=2.7=1_cp27mu
   - samtools=1.18=hd87286a_0
   - tabix=1.11=hdfd78af_0
+  - sortedcontainers