They are believed to be safer and greener. The alternatives for making processes and plants safer depend on the industry. That application has been largely displaced in favor of safer and less expensive alternatives. This resulted in safer and more efficient underwater work. Commercial screen printing now uses sensitizers far safer and less toxic than bichromates. This allowed much safer and more practical operation. This made operating the craft far safer and more reliable. It is also safer and less corrosive. It's cheaper than skiing and safer at my age. Technetium-99m has several features that make it safer than other possible isotopes. It was replaced by smallpox vaccine, a safer alternative. Some believe thorium is key to developing a new generation of cleaner, safer nuclear power. George Westinghouse invented air brakes for trains (making them both safer and faster). Exercise enhances walking speed, allowing for safer and more functional ambulation capabilities. Currently, safer and more available radioisotopes are used instead.