The paper discusses the development and field-testing of the Marine Incineration Biological Assessment Sampler (MIBAS), used to assess potential effects of incinerating hazardous wastes at sea. In 1985, the U.S. EPA developed a strategy for the research necessary for measuring environmental and public health effects of incinerating hazardous wastes at sea. One area of the strategy addressed developing a way to sample incinerator emissions and introduce them into seawater for use as test media in toxicity tests. Responding to the strategy, EPA developed the MIBAS system, a system that samples incineration flue gas, cools the emissions, and collects them in seawater-filled impingers. Particulate matter and both semi-volatile and nonvolatile organic species are collected by the train. The system uses no materials that could in themselves prove toxic to marine organisms. A recent modification of the train permits collecting emissions in the first impinger without bubbling, mimicking the situation in nature, where emissions would settle onto the ocean surface. MIBAS test have included spike-recovery, using a gas-phase spiking system to spike compounds into the emissions and then measuring them in the components of the MIBAS train.