diff --git a/src/parallel_io.c b/src/parallel_io.c
index 7ba28d6f506338ea4e9a34343203bae4e794637d..d58ee80814ed2f2641176f2191b9d9443f23459a 100644
--- a/src/parallel_io.c
+++ b/src/parallel_io.c
@@ -426,7 +426,7 @@ void prepareArray(struct engine* e, hid_t grp, char* fileName, FILE* xmfFile,
   if (h_data < 0) error("Error while creating dataspace '%s'.", props.name);
 
   /* Write unit conversion factors for this data set */
-  char buffer[FIELD_BUFFER_SIZE];
+  char buffer[FIELD_BUFFER_SIZE] = {0};
   units_cgs_conversion_string(buffer, snapshot_units, props.units);
   float baseUnitsExp[5];
   units_get_base_unit_exponents_array(baseUnitsExp, props.units);
diff --git a/src/serial_io.c b/src/serial_io.c
index e16a3351d75e176bf71d6dc1c791a37574de96f9..80eff5adace188cdc5919a52a8b55ebc6cf1dbae 100644
--- a/src/serial_io.c
+++ b/src/serial_io.c
@@ -311,7 +311,7 @@ void prepareArray(const struct engine* e, hid_t grp, char* fileName,
                    props.dimension, props.type);
 
   /* Write unit conversion factors for this data set */
-  char buffer[FIELD_BUFFER_SIZE];
+  char buffer[FIELD_BUFFER_SIZE] = {0};
   units_cgs_conversion_string(buffer, snapshot_units, props.units);
   float baseUnitsExp[5];
   units_get_base_unit_exponents_array(baseUnitsExp, props.units);
diff --git a/src/single_io.c b/src/single_io.c
index d1ef358b03a3ee00ad4375cf578c05ac17ee78fb..3e6ea192def788a66a9d8c6badf832cd7f3c1e28 100644
--- a/src/single_io.c
+++ b/src/single_io.c
@@ -323,7 +323,7 @@ void writeArray(const struct engine* e, hid_t grp, char* fileName,
                    props.dimension, props.type);
 
   /* Write unit conversion factors for this data set */
-  char buffer[FIELD_BUFFER_SIZE];
+  char buffer[FIELD_BUFFER_SIZE] = {0};
   units_cgs_conversion_string(buffer, snapshot_units, props.units);
   float baseUnitsExp[5];
   units_get_base_unit_exponents_array(baseUnitsExp, props.units);
diff --git a/src/units.c b/src/units.c
index 807640a1d2b5844e721fa5b2815acd84e968efba..ef69bb73de2fefaf208def9b4e0553f7e3ad7c24 100644
--- a/src/units.c
+++ b/src/units.c
@@ -522,7 +522,7 @@ float units_general_a_factor(const struct unit_system* us,
 void units_general_cgs_conversion_string(char* buffer,
                                          const struct unit_system* us,
                                          const float baseUnitsExponents[5]) {
-  char temp[32];
+  char temp[32] = {0};
   const double a_exp = units_general_a_factor(us, baseUnitsExponents);
   const double h_exp = 0.; /* There are no h-factors in SWIFT outputs. */