1. Cook onion, celery and garlic in hot oil in a saucepan over medium heat. Cook until vegetables are tender, stirring occasionally.
2. Add tomatoes, tomato sauce, salt, sugar, chili powder, Worcestershire and hot pepper sauce. Bring heat down to low and simmer for 45 minutes, stirring occasionally.
3. Combine cornstarch with 1 tablespoon cold water in a little bowl; stir into sauce. Cook, stirring constantly, until mixture thickens.
4. Add shrimp and green pepper. Cover and simmer for about 5-6 minutes.