Having worked with both Mac,let me try to put your mind at rest.If you ahve never been in a ships engine room or worked in a power ststion or large boiler room then it is unlikely that you will have come in contact with the dangerous type.It was used in some domestic appliances but it would appear that the danger from single or occasional exposure is minute.I get checked out annually due to constant exposure when I was at sea and working in power stations but I honestly think that my lungs suffered more from the bloody dust from me hens and from smoking than form asbestos exposure.There were times when we worked in clouds of the stuff caused by steam pipe leaks,not very nice.Shipyard workers seem to have been the main victims and also the wives who handled and washed the guys clothes.But as the item quoted by Wobs points out,the white asbestos is like talc and anyone who has ever changed a nappy would be doomed if it was really bad.BTW I was only reading recently of the natural occurance of asbestos in the US and In Oz but that was in a geological paper and I can't remember which one !! maybe a google is in order
