diff --git a/demo/markdownlint-browser.js b/demo/markdownlint-browser.js
index 88bdb947..1f4887b2 100644
--- a/demo/markdownlint-browser.js
+++ b/demo/markdownlint-browser.js
@@ -365,7 +365,7 @@ module.exports.filterTokens = filterTokens;
  */
 function getLineMetadata(params) {
   const lineMetadata = params.lines.map(
-    (line, index) => [ line, index, false, 0, false, false, false ]
+    (line, index) => [ line, index, false, 0, false, false, false, false ]
   );
   filterTokens(params, "fence", (token) => {
     lineMetadata[token.map[0]][3] = 1;
@@ -394,6 +394,11 @@ function getLineMetadata(params) {
   filterTokens(params, "hr", (token) => {
     lineMetadata[token.map[0]][6] = true;
   });
+  filterTokens(params, "html_block", (token) => {
+    for (let i = token.map[0]; i < token.map[1]; i++) {
+      lineMetadata[i][7] = true;
+    }
+  });
   return lineMetadata;
 }
 module.exports.getLineMetadata = getLineMetadata;
@@ -407,6 +412,7 @@ module.exports.getLineMetadata = getLineMetadata;
  * @param {boolean} inTable Iff in a table.
  * @param {boolean} inItem Iff in a list item.
  * @param {boolean} inBreak Iff in semantic break.
+ * @param {boolean} inHtml Iff in HTML block.
  * @returns {void}
  */
 
@@ -4210,8 +4216,9 @@ module.exports = {
   "tags": [ "headings", "atx", "spaces" ],
   "parser": "none",
   "function": function MD018(params, onError) {
-    forEachLine(lineMetadata(), (line, lineIndex, inCode) => {
+    forEachLine(lineMetadata(), (line, lineIndex, inCode, inFence, inTable, inItem, inBreak, inHtml) => {
       if (!inCode &&
+        !inHtml &&
         /^#+[^# \t]/.test(line) &&
         !/#\s*$/.test(line) &&
         !line.startsWith("#️⃣")) {
@@ -4353,8 +4360,9 @@ module.exports = {
   "tags": [ "headings", "atx_closed", "spaces" ],
   "parser": "none",
   "function": function MD020(params, onError) {
-    forEachLine(lineMetadata(), (line, lineIndex, inCode) => {
-      if (!inCode) {
+    forEachLine(lineMetadata(), (line, lineIndex, inCode, inFence, inTable, inItem, inBreak, inHtml) => {
+      if (!inCode &&
+        !inHtml) {
         const match =
           /^(#+)([ \t]*)([^#]*?[^#\\])([ \t]*)((?:\\#)?)(#+)(\s*)$/.exec(line);
         if (match) {
diff --git a/helpers/helpers.js b/helpers/helpers.js
index e8ed99bf..976b85d9 100644
--- a/helpers/helpers.js
+++ b/helpers/helpers.js
@@ -353,7 +353,7 @@ module.exports.filterTokens = filterTokens;
  */
 function getLineMetadata(params) {
   const lineMetadata = params.lines.map(
-    (line, index) => [ line, index, false, 0, false, false, false ]
+    (line, index) => [ line, index, false, 0, false, false, false, false ]
   );
   filterTokens(params, "fence", (token) => {
     lineMetadata[token.map[0]][3] = 1;
@@ -382,6 +382,11 @@ function getLineMetadata(params) {
   filterTokens(params, "hr", (token) => {
     lineMetadata[token.map[0]][6] = true;
   });
+  filterTokens(params, "html_block", (token) => {
+    for (let i = token.map[0]; i < token.map[1]; i++) {
+      lineMetadata[i][7] = true;
+    }
+  });
   return lineMetadata;
 }
 module.exports.getLineMetadata = getLineMetadata;
@@ -395,6 +400,7 @@ module.exports.getLineMetadata = getLineMetadata;
  * @param {boolean} inTable Iff in a table.
  * @param {boolean} inItem Iff in a list item.
  * @param {boolean} inBreak Iff in semantic break.
+ * @param {boolean} inHtml Iff in HTML block.
  * @returns {void}
  */
 
diff --git a/lib/md018.js b/lib/md018.js
index 007c227a..333710fe 100644
--- a/lib/md018.js
+++ b/lib/md018.js
@@ -13,8 +13,9 @@ module.exports = {
   "tags": [ "headings", "atx", "spaces" ],
   "parser": "none",
   "function": function MD018(params, onError) {
-    forEachLine(lineMetadata(), (line, lineIndex, inCode) => {
+    forEachLine(lineMetadata(), (line, lineIndex, inCode, inFence, inTable, inItem, inBreak, inHtml) => {
       if (!inCode &&
+        !inHtml &&
         /^#+[^# \t]/.test(line) &&
         !/#\s*$/.test(line) &&
         !line.startsWith("#️⃣")) {
diff --git a/lib/md020.js b/lib/md020.js
index 0207d9d6..2a6fe3a8 100644
--- a/lib/md020.js
+++ b/lib/md020.js
@@ -13,8 +13,9 @@ module.exports = {
   "tags": [ "headings", "atx_closed", "spaces" ],
   "parser": "none",
   "function": function MD020(params, onError) {
-    forEachLine(lineMetadata(), (line, lineIndex, inCode) => {
-      if (!inCode) {
+    forEachLine(lineMetadata(), (line, lineIndex, inCode, inFence, inTable, inItem, inBreak, inHtml) => {
+      if (!inCode &&
+        !inHtml) {
         const match =
           /^(#+)([ \t]*)([^#]*?[^#\\])([ \t]*)((?:\\#)?)(#+)(\s*)$/.exec(line);
         if (match) {
diff --git a/test/ignore-html-block.md b/test/ignore-html-block.md
new file mode 100644
index 00000000..4bf4f033
--- /dev/null
+++ b/test/ignore-html-block.md
@@ -0,0 +1,13 @@
+# ignore-html-block.md
+
+<style> {MD033}
+
+##Heading 1
+
+##  Heading 2
+
+##Heading 3##
+
+##  Heading 4  ##
+
+</style>
diff --git a/test/snapshots/markdownlint-test-scenarios.js.md b/test/snapshots/markdownlint-test-scenarios.js.md
index 6f31182f..530873af 100644
--- a/test/snapshots/markdownlint-test-scenarios.js.md
+++ b/test/snapshots/markdownlint-test-scenarios.js.md
@@ -19683,6 +19683,45 @@ Generated by [AVA](https://avajs.dev).
       `,
     }
 
+## ignore-html-block.md
+
+> Snapshot 1
+
+    {
+      errors: [
+        {
+          errorContext: null,
+          errorDetail: 'Element: style',
+          errorRange: [
+            1,
+            7,
+          ],
+          fixInfo: null,
+          lineNumber: 3,
+          ruleDescription: 'Inline HTML',
+          ruleInformation: 'https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/md033.md',
+          ruleNames: [
+            'MD033',
+            'no-inline-html',
+          ],
+        },
+      ],
+      fixed: `# ignore-html-block.md␊
+      ␊
+      <style> {MD033}␊
+      ␊
+      ##Heading 1␊
+      ␊
+      ##  Heading 2␊
+      ␊
+      ##Heading 3##␊
+      ␊
+      ##  Heading 4  ##␊
+      ␊
+      </style>␊
+      `,
+    }
+
 ## inconsistent_bullet_indent_same_level.md
 
 > Snapshot 1
diff --git a/test/snapshots/markdownlint-test-scenarios.js.snap b/test/snapshots/markdownlint-test-scenarios.js.snap
index e7678c20..8bbe46a8 100644
Binary files a/test/snapshots/markdownlint-test-scenarios.js.snap and b/test/snapshots/markdownlint-test-scenarios.js.snap differ