Abstract: A technique for detecting and containing liquid leaks in a liquid pumping, gas-operated diaphragm pump, and for stopping the pump operation when such leaks occur. If there is a leak in such a pump, the exhaust air gets contaminated with the liquid. With this technique the pump exhaust gas is captured in a container where any liquid within the gas is separated and is allowed to accumulate at the container bottom. The level of liquid accumulated at the container bottom is sensed, and when it reaches a predetermined level, a signal is send to a pneumatically operated shutoff valve to stop the pump operation by stopping the inflow of gas into the pump, or the outflow of liquid from the pump, or to stop the inflow of liquid into the pump. In addition, when the accumulated liquid reaches a predetermined level, a signal may be sent to a pneumatically operated warning device, turning it on.