"In the first place he had put Mr Lee a member of the public into danger by failing to instruct him that proper health and safety measures should be taken. Mr Lee had put on some protective clothing when he removed the small measures of HtH from the bulk, but had then simply carried the chemical to the pool in an old can and emptied it into the pool. It was a hazardous substance. Mr Oliver as the manager of [the Respondent] in charge of the site should have appreciated that and not put Mr Lee into danger."