The refugee crisis in certain European countries is having a significant impact on logistics. Rates have increased and air freight has become a true alternative for many shippers of time-sensitive freight. Because some borders and entry points have been closed over the past month, there have been scores of cargo trucks unable to make deliveries, and forced to wait while congestion and extended security checks take their toll on the transportation infrastructure. The surge of immigrants have also caused problems with the repositioning of equipment, creating delays in pickup operations as well. Even crossings between mainland Europe and the United Kingdom have been significant. Since margins are so thin in many areas of the supply chain, these delays and decreases in efficiency can quickly make a carrier have a loss on transporting a shipment. Some carriers choose to pass these costs on to shippers in the form of accessorial charges for wait times and delays for every hour trucks spend waiting to cross a bridge or tunnel. To make matters worse, ferry workers between the UK and France went on strike in June, causing additional delays of smaller shipments which are now being moved by LTL carriers. Critics of the situation point out that from a humanitarian point of view, the refugees involved in this crisis deserve assistance, and the supply chain cannot continue to operate in this way long term.