US scientists are taking the first step towards testing potentially hazardous chemicals on cells grown in a laboratory, without using live animals.
Two government agencies are looking into the merits of using high-speed automated robots to carry out tests.
The long-term goal is to reduce the cost, time and number of animals used in screening everything from pesticides to household chemicals.
The move follows calls for scientists to rely less on animal studies.
Robots would be able to carry out hundreds of thousands of chemical tests a day to identify chemicals with toxic effects.