The Ozone Machine

There it stood in the foyer of the Day's Inn on the southbound M1, lead and plug coiled round it and bubble wrap twined round it's handle.
'What's that for?', asked one of our party.
'That's an ozone machine', replied the receptionist. 'I've just ordered that in from another hotel. Within  an hour it can turn a smoking room into a non-smoking room. It can also keep fruit and flowers fresh for a very long time by killing bacteria. We are told not to stay in a room for more than 15 minutes while it's running'.
'Is it dangerous then?', we asked.
'It can kill a small hamster in ten minutes'.
Now we know.