diff --git a/src/Text/Pandoc/Writers/Blaze.hs b/src/Text/Pandoc/Writers/Blaze.hs
index 4bd21b789..8233043a3 100644
--- a/src/Text/Pandoc/Writers/Blaze.hs
+++ b/src/Text/Pandoc/Writers/Blaze.hs
@@ -113,8 +113,8 @@ toChunks :: Text -> [Doc Text]
 toChunks = map toDoc . T.groupBy sameStatus
   where
    toDoc t
-     | T.any (== ' ')  t = space
-     | T.any (== '\n') t = cr
+     | t == " " = space
+     | t == "\n" = cr
      | otherwise         = literal t
    sameStatus c d =
      (c == ' ' && d == ' ') ||
diff --git a/test/command/4639.md b/test/command/4639.md
index 31ac3a5d9..c35df1749 100644
--- a/test/command/4639.md
+++ b/test/command/4639.md
@@ -5,6 +5,6 @@
 \end{equation}
 ^D
 <p><span class="math display">\[\begin{equation}
-E=mc^2
+  E=mc^2
 \end{equation}\]</span></p>
 ```