In Baltimore, Maryland--sometimes called the heroin capital of the U.S.--a group of teenagers have developed an app that can track bad batches of drugs and alert nearby users. This helps drug users know when potentially lethal combinations of heroin and fentanyl are being distributed in their community. The so-called Bad Batch Boys believe that giving the information to the people that need it most has the potential to save countless lives. For more stories profiling pioneers of science and tech innovation, subscribe to Freethink at https://www.youtube.com/freethinkmedia And follow Freethink across other platforms here: Facebook: https://www.facebook.com/freethinkmedia Twitter: https://twitter.com/freethinkmedia Instagram: https://www.instagram.com/freethink Website: http://www.freethink.com