Make tagged objects explode with ray cast?

Basically, I am trying to make certain objects tagged Barrels explode when hit with a ray cast. I am getting the compiling error of BCE0077: It is not possible to invoke an expression of type ‘String’.

Here is my script:

// Prints the name of the object camera is directly looking at
var explosion : Transform;

function Update () {
    if (Input.GetButtonDown("Fire1"))
        // Get the ray going through the center of the screen
        var ray : Ray = camera.ViewportPointToRay (Vector3(0.5,0.5,0));

    // Do a raycast
    var hit : RaycastHit;

    if (Physics.Raycast (ray, hit))
        print ("I'm looking at " + hit.transform.name);
        
   if (Physics.Raycast (ray, hit))
         Debug.DrawLine (ray.origin, hit.point);

   if (Physics.Raycast (ray, hit))
         Destroy(hit.collider.gameObject);

   if (hit.collider.gameObject.tag ("Barrels")){
         Instantiate (explosion, transform.position, transform.rotation);
   }
}

if (hit.collider.gameObject.tag (“Barrels”)){

change this to :

if ( hit.collider.gameObject.tag == "Barrels" )

I also re-formatted your code =]