Ambulances are used to respond to medical emergencies by emergency medical services. Large pneumothoraces are likely to be medical emergencies requiring emergency decompression. Waterloo Fire Rescue responds to fires, medical emergencies, car accidents and chemical incidents. Individuals also store medical information on flash drives for emergencies and disaster preparation. Antiviral stockpiles prepare for shortages of antiviral medications in cases of public health emergencies. In turn this causes delays for ambulances arriving to serious emergencies. London Ambulance Service responds to medical emergencies in Finchley. These features can include sensors that monitor for medical emergencies such as falls or seizures. First responders must be trained to deal with a wide array of potential medical emergencies. Funds aim to support communities in preparing for public health emergencies, including pandemic influenza. PSAs could take control of the train in circumstances including equipment failure and emergencies. These all represent significant public health emergencies. Ensuring the availability of medical countermeasures for public health emergencies is central to BARDA's mission. Many systems have tiers of response for medical emergencies. Airports employ specialist firefighters to deal with potential ground emergencies.