diff --git a/scripts/performance-tests-kevm.sh b/scripts/performance-tests-kevm.sh
index e0f2c27563..8d1e5271c4 100755
--- a/scripts/performance-tests-kevm.sh
+++ b/scripts/performance-tests-kevm.sh
@@ -48,11 +48,11 @@ trap "exit 1"  HUP INT PIPE QUIT TERM
 trap clean_up  EXIT
 
 feature_shell() {
-  GC_DONT_GC=1 nix develop . --extra-experimental-features 'nix-command flakes' --override-input k-framework/haskell-backend $SCRIPT_DIR/../ --command bash -c "$1"
+  GC_DONT_GC=1 nix develop . --extra-experimental-features 'nix-command flakes' --override-input k-framework/haskell-backend $SCRIPT_DIR/../ --ignore-environment --command bash -c "$1"
 }
 
 master_shell() {
-  GC_DONT_GC=1 nix develop . --extra-experimental-features 'nix-command flakes' --override-input k-framework/haskell-backend github:runtimeverification/haskell-backend/$MASTER_COMMIT --command bash -c "$1"
+  GC_DONT_GC=1 nix develop . --extra-experimental-features 'nix-command flakes' --override-input k-framework/haskell-backend github:runtimeverification/haskell-backend/$MASTER_COMMIT --ignore-environment --command bash -c "$1"
 }
 
 cd $TEMPD
diff --git a/scripts/performance-tests-kontrol.sh b/scripts/performance-tests-kontrol.sh
index 41658514c4..f0bab2ff93 100755
--- a/scripts/performance-tests-kontrol.sh
+++ b/scripts/performance-tests-kontrol.sh
@@ -96,11 +96,11 @@ sed -i'' -e "s|'forge', 'build'|'forge', 'build', '--no-auto-detect'|g" src/test
 poetry lock --no-update
 
 feature_shell() {
-  GC_DONT_GC=1 nix develop . --extra-experimental-features 'nix-command flakes' --override-input kevm/k-framework/haskell-backend $SCRIPT_DIR/../ --command bash -c "$1"
+  GC_DONT_GC=1 nix develop . --extra-experimental-features 'nix-command flakes' --override-input kevm/k-framework/haskell-backend $SCRIPT_DIR/../ --ignore-environment --command bash -c "$1"
 }
 
 master_shell() {
-  GC_DONT_GC=1 nix develop . --extra-experimental-features 'nix-command flakes' --override-input kevm/k-framework/haskell-backend github:runtimeverification/haskell-backend/$MASTER_COMMIT --command bash -c "$1"
+  GC_DONT_GC=1 nix develop . --extra-experimental-features 'nix-command flakes' --override-input kevm/k-framework/haskell-backend github:runtimeverification/haskell-backend/$MASTER_COMMIT --ignore-environment --command bash -c "$1"
 }
 
 # kompile Kontrol's K dependencies