Ionic v5 (React): Env files not accessible within app

I am trying to configure .env files for our project. I have created a base .env file with a project REACT_APP_VERSION=${npm_package_version}. When running npm run build I can see the build process picking up the env variables but when trying to access the from with the app the env object is empty. Any help would be most appreciated!!

Ionic version: 5.0.3