diff --git a/doc/dev.md b/doc/dev.md
index 19f5151e..c97f7f8f 100644
--- a/doc/dev.md
+++ b/doc/dev.md
@@ -53,11 +53,12 @@ Then run:
 
 Keep notes here about how adding libraries and classes to Babashka affects the binary size.
 
-<!-- On macOS: -->
+2020/03/19 Added java.lang.NumberFormatException, java.lang.RuntimeException,
+java.util.MissingResourceException and java.util.Properties to support
+[cprop](https://github.com/tolitius/cprop/).
+41025180 - 40729908 = 295kb added.
 
-<!-- 2020/01/08, ..., 38.7mb / 11.3mb zipped -->
-<!-- Added: `clojure.data.xml`. Growth: 1.8mb / ... -->
-2020/02/21, 
+2020/02/21
 Added java.time.temporal.ChronoUnit
 40651596 - 40598260 = 53kb added.
 
diff --git a/script/lib_tests/cprop_test b/script/lib_tests/cprop_test
new file mode 100755
index 00000000..71ef87bd
--- /dev/null
+++ b/script/lib_tests/cprop_test
@@ -0,0 +1,18 @@
+#!/usr/bin/env bash
+
+set -eo pipefail
+
+export BABASHKA_CLASSPATH=$(clojure -Spath -Sdeps '{:deps {cprop {:mvn/version "0.1.16"}}}')
+
+if [ "$BABASHKA_TEST_ENV" = "native" ]; then
+    BB_CMD="./bb"
+else
+    BB_CMD="lein bb"
+fi
+
+
+CPROP_ENV="hello" $BB_CMD "
+(require '[cprop.core :refer [load-config]])
+(require '[cprop.source :refer [from-system-props from-env]])
+(println (:cprop-env (from-env)))
+"
diff --git a/script/run_lib_tests b/script/run_lib_tests
index 87e152be..10c7f271 100755
--- a/script/run_lib_tests
+++ b/script/run_lib_tests
@@ -9,3 +9,4 @@ script/lib_tests/clojure_csv_test
 script/lib_tests/regal_test
 script/lib_tests/medley_test
 script/lib_tests/babashka_curl_test
+script/lib_tests/cprop_test
diff --git a/src/babashka/impl/classes.clj b/src/babashka/impl/classes.clj
index d69a0d9a..25a057e4 100644
--- a/src/babashka/impl/classes.clj
+++ b/src/babashka/impl/classes.clj
@@ -33,7 +33,9 @@
           java.lang.Exception
           java.lang.Integer
           java.lang.Long
+          java.lang.NumberFormatException
           java.lang.Math
+          java.lang.RuntimeException
           java.util.concurrent.LinkedBlockingQueue
           java.lang.Object
           java.lang.String
@@ -90,6 +92,8 @@
           java.util.Base64$Decoder
           java.util.Base64$Encoder
           java.util.Date
+          java.util.MissingResourceException
+          java.util.Properties
           java.util.UUID
           java.util.concurrent.TimeUnit
           java.util.zip.InflaterInputStream
diff --git a/src/babashka/impl/clojure/core.clj b/src/babashka/impl/clojure/core.clj
index 72db45d8..c7e9452a 100644
--- a/src/babashka/impl/clojure/core.clj
+++ b/src/babashka/impl/clojure/core.clj
@@ -2,6 +2,7 @@
   {:no-doc true}
   (:refer-clojure :exclude [future read read-string])
   (:require [borkdude.graal.locking :as locking]
+            [sci.core :as sci]
             [sci.impl.namespaces :refer [copy-core-var]]))
 
 (defn locking* [form bindings v f & args]
@@ -29,4 +30,5 @@
    'spit (copy-core-var spit)
    'time (with-meta time* {:sci/macro true})
    'Throwable->map (copy-core-var Throwable->map)
-   'compare-and-set! (copy-core-var compare-and-set!)})
+   'compare-and-set! (copy-core-var compare-and-set!)
+   '*data-readers* (sci/new-dynamic-var '*data-readers* nil)})
diff --git a/src/babashka/main.clj b/src/babashka/main.clj
index 342d6ffe..3199d587 100644
--- a/src/babashka/main.clj
+++ b/src/babashka/main.clj
@@ -343,7 +343,9 @@ Everything after that is bound to *command-line-args*."))
                             File java.io.File
                             Long java.lang.Long
                             Math java.lang.Math
+                            NumberFormatException java.lang.NumberFormatException
                             Object java.lang.Object
+                            RuntimeException java.lang.RuntimeException
                             ProcessBuilder java.lang.ProcessBuilder
                             String java.lang.String
                             StringBuilder java.lang.StringBuilder