Unity OnTriggerEnter2D doesen't check Z Axis

Question

I am coding my game's collisions using onTriggerEnter(). The problem is that it only checks X and Y axis and not the Z one, and that is causing me some problems because my game uses the Z axis and I can't use 3D colliders for other reasons.

There is a way to check also the Z axis with onTriggerEnter or a similar function? At this moment my code is:

void OnTriggerEnter2D(Collider2D col)
{
    Debug.Log("Collision Detected");
    if(col.gameObject.tag == "Safe")
    {
        return;
    }
    else if(col.gameObject.tag == "Obstacle")
    {
        Debug.Log("Changing to Game Over scene");
        GameController.GetComponent<SceneController>().gameOver();
    }
}