I have worked in the Railway Industry for many years, and for the last ten or so we have had a strict Alcohol & Drugs Policy.
Similar comments to yours were passed when British Rail was introducing the Policy.
A few comments regarding your post.
Firstly, whilst I cannot comment authoritively on breath testing, my understanding of scenarios likely to register a 'positive' test result do not include the oft stated alcoholic mouthwash, or the Steak and Ale Pie tale.
I guess it is likely that if you undertook a breath test immediately after washing your mouth out you MAY possibly bring about a positive result, however that would be short lived as the alcohol within your mouth would rapidly disappate.
I am sure that the Police would undertake a second test somewhat later, which would then clearly be negative.
I am not sure whether the breath test result in the Police station can be admitted as evidence in a prosecution or whether a blood/urine test is done. I am sure those with the knowledge will provide the answer. Thank you in advance.
RAT 5 asked
Is the same limit applied to other public transport workers? And if not, why not?
Well I can confirm that for Railway staff deemed as 'Safety Critical' (normally those whose direct actions can impact upon the safety of staff and passengers/others) the limit is 40 milligrammes of alcohol in 100 millilitres of blood for INTERNAL INDUSTRY purposes, and 80 milligrammes of alcohol in 100 millilitres of blood and above for Police purposes.
My understanding of the reason for the equivalent of 40mg is that this is the level well above which 'false' positives may be experienced.
A person involved in a sufficiently 'serious' incident may well be tested (hopefully) by the British Transport Police and may be found to be below the legal level but subsequently found to have been over the Railway limit.
For the purposes of demonstration, it is generally accepted that 40mg equates to two units of low strength beer (1 pint) or two glasses of average strength wine.
Railway staff are counselled never to drink in the twelve hours preceeding duty and NEVER to report for duty less than eight hours after drinking.
We are guided broadly as to how to make a GENERAL calculation as to our alcohol level, but as all the trainers/instructors will say, if you need to calculate the level of alcohol in your body prior to reporting for duty then you definitely have a problem and shouldn't be reporting for duty.
Testing is undertaken by the provision of urine samples, taken and managed under 'chain of custody' arrangements.
Breath testing is carried out as a quick check, the accurate result is the urine test. To fail the breath test one would have to be pretty well close towards the legal limit as the breath equivalent of 40mg is set generously high in order to give the initial benefit of the doubt.
This debate has gone on for many months now in various different posts.
Frankly I am astounded at the way the air transportation Industry appears to have seriously mishandled both the management of the Policy and the education (in its nicest sense) of its personnel.
I see the same worries and criticism/concerns coming up here time and time again. I am sure that most if not all would be easily dealt with, and people a lot more re-assured, if the Air Trainsport Industry senior management got its collective act together properly and issued proper and cogent policies and procedures that are easily understood and accepted by all parties.
Maybe I am wrong, but the comments made on here certainly point to a serious lack of understanding of the Policy.
FInally, at risk of offending, if you reach the situation where it is necessary for you to test yourself for your alcohol levels before you report for duty then I think that is the time that you need to stand back and take a long hard view of yourself as an individual, and assess your personal situation, either subsequently with or without professional support.