--- a/libexec/bootstrap.sh
+++ b/libexec/bootstrap.sh
@@ -38,9 +38,9 @@ singularity_import linux_build
 
 BUILD_SPEC="$1"
 shift
-TMPDIR=`mktemp -d /tmp/singularity-bootstrap.XXXXXXX`
+SINGULARITY_TMPDIR=`mktemp -d /tmp/singularity-bootstrap.XXXXXXX`
 
-export TMPDIR
+export SINGULARITY_TMPDIR
 
 # Always run these checks
 SanityCheck
@@ -55,4 +55,4 @@ fi
 
 Finalize
 
-rm -rf "$TMPDIR"
+rm -rf "$SINGULARITY_TMPDIR"
diff --git a/libexec/mods/linux_build.smod b/libexec/mods/linux_build.smod
index 518f4a2..011d1ff 100644
--- a/libexec/mods/linux_build.smod
+++ b/libexec/mods/linux_build.smod
@@ -36,7 +36,7 @@ Setup() {
 }
 
 Bootstrap() {
-    if [ ! -f "$TMPDIR/type" ]; then
+    if [ ! -f "$SINGULARITY_TMPDIR/type" ]; then
         echo "Bootstrap: You must first call 'DistType'!" >&2
         exit 5
     fi
@@ -49,7 +49,7 @@ Bootstrap() {
 }
 
 InstallPkgs() {
-    if [ ! -f "$TMPDIR/type" ]; then
+    if [ ! -f "$SINGULARITY_TMPDIR/type" ]; then
         echo "InstallPkgs: You must first call 'DistType'!" >&2
         exit 5
     fi
@@ -57,7 +57,7 @@ InstallPkgs() {
 }
 
 Cleanup() {
-    if [ ! -f "$TMPDIR/type" ]; then
+    if [ ! -f "$SINGULARITY_TMPDIR/type" ]; then
         echo "Cleanup: You must first call 'DistType'!" >&2
         exit 5
     fi
@@ -82,7 +82,7 @@ DistType() {
         exit 255
     fi
 
-    echo "$TYPE" > "$TMPDIR/type"
+    echo "$TYPE" > "$SINGULARITY_TMPDIR/type"
 
     return 0
 }