diff --git a/packages/babel-helper-create-class-features-plugin/package.json b/packages/babel-helper-create-class-features-plugin/package.json
index 19101e0e5ab8..110a0deeca11 100644
--- a/packages/babel-helper-create-class-features-plugin/package.json
+++ b/packages/babel-helper-create-class-features-plugin/package.json
@@ -29,6 +29,7 @@
   },
   "devDependencies": {
     "@babel/core": "workspace:*",
-    "@babel/helper-plugin-test-runner": "workspace:*"
+    "@babel/helper-plugin-test-runner": "workspace:*",
+    "@babel/preset-env": "workspace:*"
   }
 }
diff --git a/packages/babel-helper-create-class-features-plugin/src/index.js b/packages/babel-helper-create-class-features-plugin/src/index.js
index 7c2c097c485e..7e08d2b26491 100644
--- a/packages/babel-helper-create-class-features-plugin/src/index.js
+++ b/packages/babel-helper-create-class-features-plugin/src/index.js
@@ -44,7 +44,7 @@ export function createClassFeaturePlugin({
   const constantSuper = api.assumption("constantSuper");
   const noDocumentAll = api.assumption("noDocumentAll");
 
-  if (loose) {
+  if (loose === true) {
     const explicit = [];
 
     if (setPublicClassFields !== undefined) {
diff --git a/packages/babel-helper-create-class-features-plugin/test/fixtures/plugin-proposal-class-properties/no-loose-and-assumptions-preset-env/input.js b/packages/babel-helper-create-class-features-plugin/test/fixtures/plugin-proposal-class-properties/no-loose-and-assumptions-preset-env/input.js
new file mode 100644
index 000000000000..eb0eb350654f
--- /dev/null
+++ b/packages/babel-helper-create-class-features-plugin/test/fixtures/plugin-proposal-class-properties/no-loose-and-assumptions-preset-env/input.js
@@ -0,0 +1,3 @@
+class A {
+  foo;
+}
diff --git a/packages/babel-helper-create-class-features-plugin/test/fixtures/plugin-proposal-class-properties/no-loose-and-assumptions-preset-env/options.json b/packages/babel-helper-create-class-features-plugin/test/fixtures/plugin-proposal-class-properties/no-loose-and-assumptions-preset-env/options.json
new file mode 100644
index 000000000000..29b0d05fdcab
--- /dev/null
+++ b/packages/babel-helper-create-class-features-plugin/test/fixtures/plugin-proposal-class-properties/no-loose-and-assumptions-preset-env/options.json
@@ -0,0 +1,8 @@
+{
+  "validateLogs": true,
+  "presets": [["env", { "shippedProposals": true }]],
+  "assumptions": {
+    "setPublicClassFields": true
+  },
+  "targets": "chrome 70"
+}
diff --git a/packages/babel-helper-create-class-features-plugin/test/fixtures/plugin-proposal-class-properties/no-loose-and-assumptions-preset-env/output.js b/packages/babel-helper-create-class-features-plugin/test/fixtures/plugin-proposal-class-properties/no-loose-and-assumptions-preset-env/output.js
new file mode 100644
index 000000000000..063a057f52c0
--- /dev/null
+++ b/packages/babel-helper-create-class-features-plugin/test/fixtures/plugin-proposal-class-properties/no-loose-and-assumptions-preset-env/output.js
@@ -0,0 +1,6 @@
+class A {
+  constructor() {
+    this.foo = void 0;
+  }
+
+}
diff --git a/packages/babel-helper-create-class-features-plugin/test/fixtures/plugin-proposal-class-properties/no-loose-and-assumptions-preset-env/stderr.txt b/packages/babel-helper-create-class-features-plugin/test/fixtures/plugin-proposal-class-properties/no-loose-and-assumptions-preset-env/stderr.txt
new file mode 100644
index 000000000000..8b137891791f
--- /dev/null
+++ b/packages/babel-helper-create-class-features-plugin/test/fixtures/plugin-proposal-class-properties/no-loose-and-assumptions-preset-env/stderr.txt
@@ -0,0 +1 @@
+
diff --git a/packages/babel-helper-create-class-features-plugin/test/fixtures/plugin-proposal-class-properties/warn-loose-and-assumptions-preset-env/input.js b/packages/babel-helper-create-class-features-plugin/test/fixtures/plugin-proposal-class-properties/warn-loose-and-assumptions-preset-env/input.js
new file mode 100644
index 000000000000..eb0eb350654f
--- /dev/null
+++ b/packages/babel-helper-create-class-features-plugin/test/fixtures/plugin-proposal-class-properties/warn-loose-and-assumptions-preset-env/input.js
@@ -0,0 +1,3 @@
+class A {
+  foo;
+}
diff --git a/packages/babel-helper-create-class-features-plugin/test/fixtures/plugin-proposal-class-properties/warn-loose-and-assumptions-preset-env/options.json b/packages/babel-helper-create-class-features-plugin/test/fixtures/plugin-proposal-class-properties/warn-loose-and-assumptions-preset-env/options.json
new file mode 100644
index 000000000000..4297b3db2cbd
--- /dev/null
+++ b/packages/babel-helper-create-class-features-plugin/test/fixtures/plugin-proposal-class-properties/warn-loose-and-assumptions-preset-env/options.json
@@ -0,0 +1,8 @@
+{
+  "validateLogs": true,
+  "presets": [["env", { "loose": true, "shippedProposals": true }]],
+  "assumptions": {
+    "setPublicClassFields": true
+  },
+  "targets": "chrome 70"
+}
diff --git a/packages/babel-helper-create-class-features-plugin/test/fixtures/plugin-proposal-class-properties/warn-loose-and-assumptions-preset-env/output.js b/packages/babel-helper-create-class-features-plugin/test/fixtures/plugin-proposal-class-properties/warn-loose-and-assumptions-preset-env/output.js
new file mode 100644
index 000000000000..063a057f52c0
--- /dev/null
+++ b/packages/babel-helper-create-class-features-plugin/test/fixtures/plugin-proposal-class-properties/warn-loose-and-assumptions-preset-env/output.js
@@ -0,0 +1,6 @@
+class A {
+  constructor() {
+    this.foo = void 0;
+  }
+
+}
diff --git a/packages/babel-helper-create-class-features-plugin/test/fixtures/plugin-proposal-class-properties/warn-loose-and-assumptions-preset-env/stderr.txt b/packages/babel-helper-create-class-features-plugin/test/fixtures/plugin-proposal-class-properties/warn-loose-and-assumptions-preset-env/stderr.txt
new file mode 100644
index 000000000000..8b137891791f
--- /dev/null
+++ b/packages/babel-helper-create-class-features-plugin/test/fixtures/plugin-proposal-class-properties/warn-loose-and-assumptions-preset-env/stderr.txt
@@ -0,0 +1 @@
+
diff --git a/yarn.lock b/yarn.lock
index b0088ae93c14..af1a48b62520 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -429,6 +429,7 @@ __metadata:
     "@babel/helper-plugin-test-runner": "workspace:*"
     "@babel/helper-replace-supers": "workspace:^7.13.0"
     "@babel/helper-split-export-declaration": "workspace:^7.12.13"
+    "@babel/preset-env": "workspace:*"
   peerDependencies:
     "@babel/core": ^7.0.0
   languageName: unknown