Some animal tests take months or years to conduct and analyze (e.g., 4-5 years, in the case of rodent cancer studies), at a cost of hundreds of thousands—and sometimes millions—of dollars per substance examined (e.g., $2 to $4 million per two-species lifetime cancer study).
The inefficiency and exorbitant costs associated with animal testing makes it impossible for regulators to adequately evaluate the potential effects of the more than 100,000 chemicals currently in commerce worldwide, let alone study the effects of myriad combinations of chemicals to which humans and wildlife are exposed, at low doses, every day throughout our lives.
In contrast, computer modeling techniques are lightning-fast, and many cell-based in vitro methods are amenable to “high throughput” automation using robotics—all at a much lower cost than animal tests.