diff --git a/package.json b/package.json
index 5581876..06a22a3 100644
--- a/package.json
+++ b/package.json
@@ -62,7 +62,7 @@
     "typescript": "^4.0.3"
   },
   "optionalDependencies": {
-    "macos-export-certificate-and-key": "^1.1.1",
-    "win-export-certificate-and-key": "^2.0.0"
+    "macos-export-certificate-and-key": "^1.2.0",
+    "win-export-certificate-and-key": "^2.1.0"
   }
 }
diff --git a/src/impl.ts b/src/impl.ts
index c6058a5..5d74352 100644
--- a/src/impl.ts
+++ b/src/impl.ts
@@ -96,7 +96,7 @@ export async function * unixAsyncImpl(env: Record<string, string | undefined>):
   }
 }
 
-export function * windowsImpl(): Iterable<string> {
+export function * windowsSyncImpl(): Iterable<string> {
   let exportSystemCertificates;
   // try/catch helps bundlers deal with optional dependencies
   // eslint-disable-next-line no-useless-catch
@@ -110,7 +110,21 @@ export function * windowsImpl(): Iterable<string> {
   yield * exportSystemCertificates({ store: 'CA' });
 }
 
-export function * macosImpl(): Iterable<string> {
+export async function * windowsAsyncImpl(): AsyncIterable<string> {
+  let exportSystemCertificatesAsync;
+  // try/catch helps bundlers deal with optional dependencies
+  // eslint-disable-next-line no-useless-catch
+  try {
+    // eslint-disable-next-line @typescript-eslint/no-var-requires
+    ({ exportSystemCertificatesAsync } = require('win-export-certificate-and-key'));
+  } catch (err) {
+    throw err;
+  }
+  yield * await exportSystemCertificatesAsync({ store: 'ROOT' });
+  yield * await exportSystemCertificatesAsync({ store: 'CA' });
+}
+
+export function * macosSyncImpl(): Iterable<string> {
   let exportSystemCertificates;
   // try/catch helps bundlers deal with optional dependencies
   // eslint-disable-next-line no-useless-catch
@@ -122,3 +136,16 @@ export function * macosImpl(): Iterable<string> {
   }
   yield * exportSystemCertificates();
 }
+
+export async function * macosAsyncImpl(): AsyncIterable<string> {
+  let exportSystemCertificatesAsync;
+  // try/catch helps bundlers deal with optional dependencies
+  // eslint-disable-next-line no-useless-catch
+  try {
+    // eslint-disable-next-line @typescript-eslint/no-var-requires
+    ({ exportSystemCertificatesAsync } = require('macos-export-certificate-and-key'));
+  } catch (err) {
+    throw err;
+  }
+  yield * await exportSystemCertificatesAsync();
+}
diff --git a/src/index.ts b/src/index.ts
index 51a8a85..f59c1f3 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1,6 +1,5 @@
-import { unixSyncImpl, unixAsyncImpl, windowsImpl, macosImpl } from './impl';
+import { unixSyncImpl, unixAsyncImpl, windowsSyncImpl, macosSyncImpl, windowsAsyncImpl, macosAsyncImpl } from './impl';
 import { rootCertificates } from 'tls';
-import { once } from 'events';
 
 export interface Options {
   env?: Record<string, string | undefined>;
@@ -20,42 +19,26 @@ function maybeAddNodeCertificates(certs: Set<string>, opts: Options): string[] {
 export function systemCertsSync(opts: Options = {}): string[] {
   let certs: Set<string>;
   if (process.platform === 'win32') {
-    certs = new Set(windowsImpl());
+    certs = new Set(windowsSyncImpl());
   } else if (process.platform === 'darwin') {
-    certs = new Set(macosImpl());
+    certs = new Set(macosSyncImpl());
   } else {
     certs = new Set(unixSyncImpl(opts.env ?? process.env));
   }
   return maybeAddNodeCertificates(certs, opts);
 }
 
-// eslint-disable-next-line camelcase
-declare const __webpack_require__: unknown;
-
 export async function systemCertsAsync(opts: Options = {}): Promise<string[]> {
-  let certs: Set<string>;
-  if (process.platform === 'win32' || process.platform === 'darwin') {
-    const script = `
-    const { parentPort } = require('worker_threads');
-    const iterable = require(${JSON.stringify(__filename)}).systemCertsSync(${JSON.stringify(opts)});
-    parentPort.postMessage(new Set(iterable));
-    `;
-    try {
-      // eslint-disable-next-line camelcase
-      if (typeof __webpack_require__ !== 'undefined') {
-        throw new Error('Not attempting to start worker thread from bundled application');
-      }
-
-      const { Worker } = await import('worker_threads');
-      const worker = new Worker(script, { eval: true });
-      const [result] = await once(worker, 'message');
-      certs = result;
-    } catch (err: any) {
-      opts.asyncFallbackError = err;
-      return systemCertsSync();
+  const certs = new Set<string>();
+  if (process.platform === 'win32') {
+    for await (const cert of windowsAsyncImpl()) {
+      certs.add(cert);
+    }
+  } else if (process.platform === 'darwin') {
+    for await (const cert of macosAsyncImpl()) {
+      certs.add(cert);
     }
   } else {
-    certs = new Set();
     for await (const cert of unixAsyncImpl(opts.env ?? process.env)) {
       certs.add(cert);
     }