Brown flour in bacon drippings in large Dutch oven, stirring constantly.
Add onions, green pepper and celery; simmer, covered, for 5 minutes.
Add toma- toes and shrimp; simmer, covered, until shrimp turn pink.
Add seasonings, thyme, bay leaves and 3 quarts hot water; simmer for about 3 hours, stirring occa- sionally.
Serve over rice.