diff --git a/skiplang/compiler/src/SkipParser.sk b/skiplang/compiler/src/SkipParser.sk
index ac3aa622a..731c175da 100644
--- a/skiplang/compiler/src/SkipParser.sk
+++ b/skiplang/compiler/src/SkipParser.sk
@@ -33,6 +33,7 @@ mutable class SkipParser{
   lazy: Bool,
   tokenLexer: mutable SkipLexer.SkipCoreLexer,
   templateLexer: mutable SkipLexer.TemplateLexer,
+  accessedEnvVars: mutable Set<String> = mutable Set[],
 } extends Parser.Parser {
   static fun create(source: String, lazy: Bool): mutable this {
     lexingPosition = Lexer.LexingPosition::create(source);
@@ -54,6 +55,10 @@ mutable class SkipParser{
     };
   }
 
+  readonly fun getAccessedEnvVars(): SortedSet<String> {
+    SortedSet::createFromIterator(this.accessedEnvVars.values())
+  }
+
   mutable fun createPeekParser(): mutable this {
     mutable static{
       lazy => this.lazy,
@@ -4791,6 +4796,8 @@ mutable class SkipParser{
     };
     closeParen = this.eatTree(TokenKind.CLOSE_PAREN());
 
+    this.accessedEnvVars.insert(varName.getToken().stringLiteralValue());
+
     ParseTree.EnvMacroTree{
       range => this.createRange(start),
       envKeyword,
@@ -5108,7 +5115,7 @@ fun parseSource(
   source: String,
   isLazy: Bool,
   filename: String = "",
-): Parser.ParseResults {
+): (Parser.ParseResults, SortedSet<String>) {
   parser = SkipParser::create(source, isLazy);
   tree = parser.parseSourceUnit();
   allErrors = parser.getErrors();
@@ -5124,7 +5131,11 @@ fun parseSource(
   if (errors.isEmpty() && !isLazy) {
     Parser.validateParse(tokens, tree, filename);
   };
-  Parser.ParseResults{tokens, comments => parser.getComments(), tree, errors};
+
+  (
+    Parser.ParseResults{tokens, comments => parser.getComments(), tree, errors},
+    parser.getAccessedEnvVars(),
+  )
 }
 
 fun getNamedParameterDefaultValue(tree: ParseTree): ParseTree {
diff --git a/skiplang/compiler/src/compile.sk b/skiplang/compiler/src/compile.sk
index 282ccb9b3..6bb3a3cf6 100644
--- a/skiplang/compiler/src/compile.sk
+++ b/skiplang/compiler/src/compile.sk
@@ -245,28 +245,7 @@ fun getOrInitializeBackend(context: mutable SKStore.Context): SKStore.EagerDir {
       };
 
       if (conf.emit == "sklib") {
-        accessed_env_vars = context.getGlobal(
-          FileCache.kEnvAccessGlobal,
-        ) match {
-        | None() -> SortedSet[]
-        | Some(envMapFile) ->
-          FileCache.EnvMapFile::type(envMapFile)
-            .value.maybeGet(conf.lib_name)
-            .default(SortedSet[])
-        };
-        env_dir = SKStore.EHandle(
-          SKStore.SID::keyType,
-          SKStore.StringFile::type,
-          SKStore.DirName::create(
-            `/packageEnv/${conf.lib_name.default("_default")}/`,
-          ),
-        );
-        env = SortedMap::createFromIterator(
-          accessed_env_vars
-            .map(v -> (v, env_dir.unsafeGet(context, SKStore.SID(v)).value))
-            .iterator(),
-        );
-        compile_sklib(conf, env);
+        compile_sklib(context, conf);
         return void
       };
 
@@ -423,11 +402,21 @@ fun compile_binary(
   })
 }
 
-fun compile_sklib(
-  conf: Config.Config,
-  env_vars: SortedMap<String, String>,
-): void {
+fun compile_sklib(context: mutable SKStore.Context, conf: Config.Config): void {
   runCompilerPhase("native/write_sklib", () -> {
+    accessed_env_vars = SortedSet::createFromItems(
+      FileCache.packageEnvAccessDir.getArray(
+        context,
+        SKStore.SID(conf.lib_name.fromSome()),
+      ).map(v -> v.value),
+    );
+    env_dir = FileCache.packageEnvDir(conf.lib_name);
+    env_vars = SortedMap::createFromIterator(
+      accessed_env_vars
+        .map(v -> (v, env_dir.unsafeGet(context, SKStore.SID(v)).value))
+        .iterator(),
+    );
+
     // NOTE: Static libraries (`.a` archives) provided as input files are
     // bundled into the `sklib`.
     sklib = mutable SklibBuilder(
diff --git a/skiplang/compiler/src/convertTree.sk b/skiplang/compiler/src/convertTree.sk
index 68f26fa4e..030b8432d 100644
--- a/skiplang/compiler/src/convertTree.sk
+++ b/skiplang/compiler/src/convertTree.sk
@@ -884,7 +884,6 @@ class Converter{file: FileCache.InputSource} {
   fun convertEnvMacro(_range: FileRange, varName: ParseTree): SkipAst.Expr_ {
     SkipAst.EnvMacro(
       this.createName(varName, varName.getToken().stringLiteralValue()),
-      this.file.pkg_opt,
     )
   }
 
diff --git a/skiplang/compiler/src/skfmt.sk b/skiplang/compiler/src/skfmt.sk
index 456b807de..f9fb6e710 100644
--- a/skiplang/compiler/src/skfmt.sk
+++ b/skiplang/compiler/src/skfmt.sk
@@ -11,7 +11,7 @@ fun prettyPrint(
   contents: String,
   filename: String,
 ): Result<String, SkipError.Error> {
-  parsed = SkipParser.parseSource(contents, false);
+  (parsed, _) = SkipParser.parseSource(contents, false);
   if (parsed.errors.size() > 0) {
     // Parse errors are expected. Exceptions are bugs.
     Failure(
diff --git a/skiplang/compiler/src/skipAst.sk b/skiplang/compiler/src/skipAst.sk
index 4dfcaaed2..4b84bb07a 100644
--- a/skiplang/compiler/src/skipAst.sk
+++ b/skiplang/compiler/src/skipAst.sk
@@ -365,7 +365,7 @@ base class Expr_ {
     functionName: ?Name,
     body: Expr,
   )
-  | EnvMacro(Name, ?String)
+  | EnvMacro(Name)
   | MacroDot(Expr, Name)
   | MacroStaticDot(Expr, Name)
 }
diff --git a/skiplang/compiler/src/skipAstPp.sk b/skiplang/compiler/src/skipAstPp.sk
index 972ab5b50..82fc4e8f1 100644
--- a/skiplang/compiler/src/skipAstPp.sk
+++ b/skiplang/compiler/src/skipAstPp.sk
@@ -861,7 +861,7 @@ fun expr(o: mutable BufferedPrinter.Out, e: SkipAst.Expr): void {
     };
     o.out(") ");
     expr(o, body)
-  | SkipAst.EnvMacro(varName, _) ->
+  | SkipAst.EnvMacro(varName) ->
     o.out("#env (");
     o.out(literal_to_string(SkipAst.StringLiteral(varName.i1)));
     o.out(")")
diff --git a/skiplang/compiler/src/skipExpand.sk b/skiplang/compiler/src/skipExpand.sk
index fdad9bb8d..4c6b6ff84 100644
--- a/skiplang/compiler/src/skipExpand.sk
+++ b/skiplang/compiler/src/skipExpand.sk
@@ -3419,34 +3419,7 @@ fun expr_(
       functionName,
       expr(context, env, body),
     )
-  | A.EnvMacro(varName, pkg_opt) ->
-    pkg_env = SKStore.EHandle(
-      SKStore.SID::keyType,
-      SKStore.StringFile::type,
-      // FIXME: Ensure package names cannot start with an underscore to avoid clash with `_default`.
-      SKStore.DirName::create(`/packageEnv/${pkg_opt.default("_default")}/`),
-    );
-    name = varName.i1;
-    value = pkg_env.maybeGet(context, SKStore.SID(name)) match {
-    | None() ->
-      SkipError.error(varName.i0, `Environment variable ${name} is not set.`)
-    | Some(v) -> v.value
-    };
-    // Record access to env variable.
-    cur_env_map = context.getGlobal(FileCache.kEnvAccessGlobal) match {
-    | None() -> SortedMap[]
-    | Some(envMapFile) -> FileCache.EnvMapFile::type(envMapFile).value
-    };
-    context.setGlobal(
-      FileCache.kEnvAccessGlobal,
-      FileCache.EnvMapFile(
-        cur_env_map.set(
-          pkg_opt,
-          cur_env_map.maybeGet(pkg_opt).default(SortedSet[]).set(name),
-        ),
-      ),
-    );
-    A.Literal(A.StringLiteral(value))
+  | A.EnvMacro(varName) -> A.EnvMacro(varName)
   }
 }
 
diff --git a/skiplang/compiler/src/skipMain.sk b/skiplang/compiler/src/skipMain.sk
index c43c769d7..3b8fc96df 100644
--- a/skiplang/compiler/src/skipMain.sk
+++ b/skiplang/compiler/src/skipMain.sk
@@ -15,9 +15,9 @@ fun type_program(
 ): SKStore.EHandle<SKStore.SID, SkipTyping.DefFile> {
   parsed_program = FileCache.fileDir.map(
     FileCache.InputSource::keyType,
-    SkipParse.DefsFile::type,
+    SkipParse.DefsWithAccessedEnvVarsFile::type,
     context,
-    SkipParse.astDirName,
+    SKStore.DirName::create("/astAndAccessedEnvVarsCache/"),
     (context, writer, key, sources) ~> {
       source = sources.first;
       SkipError.catchErrors(0, context, () -> {
@@ -26,7 +26,35 @@ fun type_program(
     },
   );
 
-  (defsDir, childDir) = SkipExpand.program(context, parsed_program);
+  _ = parsed_program.map(
+    SKStore.SID::keyType,
+    SKStore.StringFile::type,
+    context,
+    FileCache.packageEnvAccessDirName,
+    (_context, writer, key, values) ~> {
+      writer.setArray(
+        SKStore.SID(key.pkg_opt.default(FileCache.kAnonymousPackageName)),
+        values
+          .getUnique()
+          .fromSome()
+          .accessed_env_vars.values()
+          .map(v -> SKStore.StringFile(v))
+          .collect(Array),
+      )
+    },
+  );
+
+  ast = parsed_program.map(
+    FileCache.InputSource::keyType,
+    SkipParse.DefsFile::type,
+    context,
+    SkipParse.astDirName,
+    (_context, writer, key, values) ~> {
+      writer.set(key, SkipParse.DefsFile(values.getUnique().fromSome().defs))
+    },
+  );
+
+  (defsDir, childDir) = SkipExpand.program(context, ast);
   inhDir = SkipInherit.populateClassesDir(context);
   SkipNaming.populateClasses(context, defsDir, inhDir, childDir);
   SkipNaming.populateFuns(context, defsDir);
diff --git a/skiplang/compiler/src/skipNaming.sk b/skiplang/compiler/src/skipNaming.sk
index 5b3b1f4cc..8edadce28 100644
--- a/skiplang/compiler/src/skipNaming.sk
+++ b/skiplang/compiler/src/skipNaming.sk
@@ -3660,6 +3660,18 @@ fun expandForEachMacro(
   N.Bind(iteratorn, getIterator, flagged)
 }
 
+fun expandEnvMacro(context: mutable SKStore.Context, varName: A.Name): N.Expr_ {
+  (pos, name) = varName;
+  value = FileCache.packageEnvDir(pos.file.pkg_opt).maybeGet(
+    context,
+    SKStore.SID(name),
+  ) match {
+  | None() -> SkipError.error(pos, `Environment variable ${name} is not set.`)
+  | Some(v) -> v.value
+  };
+  N.Literal(A.StringLiteral(value))
+}
+
 fun reportDuplicateMacro(
   pos: FileRange,
   id: String,
@@ -3816,9 +3828,8 @@ fun expr_(
   | A.Literal(l) -> N.Literal(l)
   | A.Var(n) -> N.Var(n)
   | A.MacroVar(n) -> expandExpressionMacro(env, n)
-  | A.Seq _
-  | A.EnvMacro _ ->
-    invariant_violation("assert false")
+  | A.Seq _ -> invariant_violation("assert false")
+  | A.EnvMacro(n) -> expandEnvMacro(context, n)
   | A.If(e1, e2, e3) ->
     N.If(
       expr(context, acc, env, e1),
diff --git a/skiplang/compiler/src/skipParse.sk b/skiplang/compiler/src/skipParse.sk
index f7b7c2319..eb139a2d5 100644
--- a/skiplang/compiler/src/skipParse.sk
+++ b/skiplang/compiler/src/skipParse.sk
@@ -68,6 +68,18 @@ const packageDir: SKStore.EHandle<
   packageDirName,
 );
 
+const packageEnvAccessDirName: SKStore.DirName = SKStore.DirName::create(
+  "/packageEnvAccess/",
+);
+const packageEnvAccessDir: SKStore.EHandle<
+  SKStore.SID,
+  SKStore.StringFile,
+> = SKStore.EHandle(
+  SKStore.SID::keyType,
+  SKStore.StringFile::type,
+  packageEnvAccessDirName,
+);
+
 fun pkgDelta(
   old_pkg: InputPackageFiles,
   new_pkg: InputPackageFiles,
@@ -205,17 +217,33 @@ fun writeFiles(
   }
 }
 
+// FIXME: Ensure package names cannot start with an underscore to avoid clash with `_anonymous`.
+const kAnonymousPackageName: String = "_anonymous";
+
+fun packageEnvDirName(pkg_opt: ?String): SKStore.DirName {
+  SKStore.DirName::create(
+    `/packageEnv/${pkg_opt.default(kAnonymousPackageName)}/`,
+  )
+}
+
+fun packageEnvDir(
+  pkg_opt: ?String,
+): SKStore.EHandle<SKStore.SID, SKStore.StringFile> {
+  SKStore.EHandle(
+    SKStore.SID::keyType,
+    SKStore.StringFile::type,
+    packageEnvDirName(pkg_opt),
+  )
+}
+
 fun updatePackageEnv(
   context: mutable SKStore.Context,
   pkg_opt: ?String,
   env: Array<(String, String)>,
 ): void {
-  envDirName = SKStore.DirName::create(
-    `/packageEnv/${pkg_opt.default("_default")}/`,
-  );
+  envDirName = packageEnvDirName(pkg_opt);
   envDir = context.unsafeMaybeGetEagerDir(envDirName) match {
-  | Some _ ->
-    SKStore.EHandle(SKStore.SID::keyType, SKStore.StringFile::type, envDirName)
+  | Some _ -> packageEnvDir(pkg_opt)
   | None _ ->
     context.mkdir(SKStore.SID::keyType, SKStore.StringFile::type, envDirName)
   };
@@ -236,12 +264,6 @@ fun updatePackageEnv(
   };
 }
 
-const kEnvAccessGlobal: String = "ACCESSED_ENV_MAP";
-
-class EnvMapFile(
-  value: SortedMap<?String, SortedSet<String>>,
-) extends SKStore.File
-
 module end;
 
 module SkipParse;
@@ -254,11 +276,18 @@ const astDir: SKStore.EHandle<SKStore.SID, DefsFile> = SKStore.EHandle(
 );
 
 class DefsFile(value: List<SkipAst.Definition>) extends SKStore.File
+class DefsWithAccessedEnvVarsFile(
+  defs: List<SkipAst.Definition>,
+  accessed_env_vars: SortedSet<String>,
+) extends SKStore.File
 
-fun parseFile(file: FileCache.InputSource, source: String): DefsFile {
-  fileResult = SkipParser.parseSource(source, true);
-  ast = parseToAst(file, fileResult);
-  DefsFile(ast)
+fun parseFile(
+  file: FileCache.InputSource,
+  source: String,
+): DefsWithAccessedEnvVarsFile {
+  (fileResult, accessed_env_vars) = SkipParser.parseSource(source, true);
+  defs = parseToAst(file, fileResult);
+  DefsWithAccessedEnvVarsFile(defs, accessed_env_vars)
 }
 
 fun parseToAst(