In A Large Bowl, Mix The Celery, Onions, Green Pepper, Ketchup, Water, Barbeque Sauce, Vinegar, And Hot Pepper Sauce. Season With Chili Powder, Salt, And Pepper. Place The Roast In A Slow Cooker, And Cover With The Sauce Mixture. Cover, And Cook On Low For Approximately 12 Hours. Shred The Meat With A Fork. Increase Cooking Temperature To High, And Continue Cooking Until Most Of The Liquid Has Been Reduced.