Detention and seizure of goods require payment of tax or security and prescribed penalties to secure release in transit violations. Detention or seizure of goods and conveyances in transit may be ordered where transport or storage contravenes the Act; release requires either payment of tax and prescribed penalty, payment of a reduced amount if the owner does not come forward, or furnishing prescribed security. The proper officer must serve a detention/seizure order, issue a notice specifying tax and penalty, provide an opportunity to be heard before determination, and may initiate further proceedings if amounts remain unpaid, with a shortened compliance period for perishable or hazardous goods.