The first chart recorder for environmental monitoring was designed by American inventor J.C. Stevens while working for Leupold & Stevens in Portland, Oregon and was issued a patent for this design in 1915. Chart recorders are still used in applications where instant visual feedback is required or where users do not have the need, opportunity or technical ability to download and view data on a computer or where no electrical power is available (such as in hazardous zones on an oil rig or in remote ecological studies). However, dataloggers' decreasing cost and power requirements allow them to increasingly replace chart recorders, even in situations where battery power is the only option.