diff --git a/cmd/soong_ui/main.go b/cmd/soong_ui/main.go
index d8cb47a..e3ccb6c 100644
--- a/cmd/soong_ui/main.go
+++ b/cmd/soong_ui/main.go
@@ -16,7 +16,6 @@
 
 import (
 	"context"
-	"encoding/json"
 	"flag"
 	"fmt"
 	"io/ioutil"
@@ -36,11 +35,6 @@
 	"android/soong/ui/tracer"
 )
 
-const (
-	configDir  = "vendor/google/tools/soong_config"
-	jsonSuffix = "json"
-)
-
 // A command represents an operation to be executed in the soong build
 // system.
 type command struct {
@@ -117,43 +111,6 @@
 	return indexList(s, list) != -1
 }
 
-func loadEnvConfig(config build.Config) error {
-	bc := os.Getenv("ANDROID_BUILD_ENVIRONMENT_CONFIG")
-	if bc == "" {
-		return nil
-	}
-	configDirs := []string{
-		os.Getenv("ANDROID_BUILD_ENVIRONMENT_CONFIG_DIR"),
-		config.OutDir(),
-		configDir,
-	}
-	var cfgFile string
-	for _, dir := range configDirs {
-		cfgFile = filepath.Join(os.Getenv("TOP"), dir, fmt.Sprintf("%s.%s", bc, jsonSuffix))
-		if _, err := os.Stat(cfgFile); err == nil {
-			break
-		}
-	}
-
-	envVarsJSON, err := ioutil.ReadFile(cfgFile)
-	if err != nil {
-		fmt.Fprintf(os.Stderr, "\033[33mWARNING:\033[0m failed to open config file %s: %s\n", cfgFile, err.Error())
-		return nil
-	}
-
-	var envVars map[string]map[string]string
-	if err := json.Unmarshal(envVarsJSON, &envVars); err != nil {
-		return fmt.Errorf("env vars config file: %s did not parse correctly: %s", cfgFile, err.Error())
-	}
-	for k, v := range envVars["env"] {
-		if os.Getenv(k) != "" {
-			continue
-		}
-		config.Environment().Set(k, v)
-	}
-	return nil
-}
-
 // Main execution of soong_ui. The command format is as follows:
 //
 //    soong_ui <command> [<arg 1> <arg 2> ... <arg n>]
@@ -218,11 +175,6 @@
 
 	config := c.config(buildCtx, args...)
 
-	if err := loadEnvConfig(config); err != nil {
-		fmt.Fprintf(os.Stderr, "failed to parse env config files: %v", err)
-		os.Exit(1)
-	}
-
 	build.SetupOutDir(buildCtx, config)
 
 	if config.UseBazel() && config.Dist() {
diff --git a/ui/build/config.go b/ui/build/config.go
index b6d0d27..a731932 100644
--- a/ui/build/config.go
+++ b/ui/build/config.go
@@ -15,7 +15,9 @@
 package build
 
 import (
+	"encoding/json"
 	"fmt"
+	"io/ioutil"
 	"os"
 	"path/filepath"
 	"runtime"
@@ -30,6 +32,11 @@
 	smpb "android/soong/ui/metrics/metrics_proto"
 )
 
+const (
+	envConfigDir  = "vendor/google/tools/soong_config"
+	jsonSuffix    = "json"
+)
+
 type Config struct{ *configImpl }
 
 type configImpl struct {
@@ -128,6 +135,43 @@
 	}
 }
 
+func loadEnvConfig(config *configImpl) error {
+	bc := os.Getenv("ANDROID_BUILD_ENVIRONMENT_CONFIG")
+	if bc == "" {
+		return nil
+	}
+	configDirs := []string{
+		os.Getenv("ANDROID_BUILD_ENVIRONMENT_CONFIG_DIR"),
+		config.OutDir(),
+		envConfigDir,
+	}
+	var cfgFile string
+	for _, dir := range configDirs {
+		cfgFile = filepath.Join(os.Getenv("TOP"), dir, fmt.Sprintf("%s.%s", bc, jsonSuffix))
+		if _, err := os.Stat(cfgFile); err == nil {
+			break
+		}
+	}
+
+	envVarsJSON, err := ioutil.ReadFile(cfgFile)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "\033[33mWARNING:\033[0m failed to open config file %s: %s\n", cfgFile, err.Error())
+		return nil
+	}
+
+	var envVars map[string]map[string]string
+	if err := json.Unmarshal(envVarsJSON, &envVars); err != nil {
+		return fmt.Errorf("env vars config file: %s did not parse correctly: %s", cfgFile, err.Error())
+	}
+	for k, v := range envVars["env"] {
+		if os.Getenv(k) != "" {
+			continue
+		}
+		config.Environment().Set(k, v)
+	}
+	return nil
+}
+
 func NewConfig(ctx Context, args ...string) Config {
 	ret := &configImpl{
 		environ:       OsEnvironment(),
@@ -157,6 +201,12 @@
 		ret.environ.Set("OUT_DIR", outDir)
 	}
 
+	// loadEnvConfig needs to know what the OUT_DIR is, so it should
+	// be called after we determine the appropriate out directory.
+	if err := loadEnvConfig(ret); err != nil {
+		ctx.Fatalln("Failed to parse env config files: %v", err)
+	}
+
 	if distDir, ok := ret.environ.Get("DIST_DIR"); ok {
 		ret.distDir = filepath.Clean(distDir)
 	} else {
@@ -988,7 +1038,7 @@
 }
 
 func (c *configImpl) UseRBE() bool {
-	if v, ok := c.environ.Get("USE_RBE"); ok {
+	if v, ok := c.Environment().Get("USE_RBE"); ok {
 		v = strings.TrimSpace(v)
 		if v != "" && v != "false" {
 			return true