The first Health and Safety 'Loo' book (possibly)

This isn't a book in the accepted sense. It's a collection of fictitious, humorous letters that might have been written by (or in some cases to) the appropriate local Health and Safety executives in bygone days. There are 60 letters in all, concerning a variety of actual or imaginary events. Where actual, each has been researched as far as possible to achieve a degree of authenticity.