House Bill No. 6278 seeks to limit the use of animal testing by manufacturers and contract testing facilities when alternative testing methods are available. The bill defines "alternative test methods" as those that provide equivalent or superior scientific quality without using animals or that minimize animal use and suffering when non-animal methods are not feasible. It includes specific definitions for terms such as "animal," "animal test method," and "validation body." The bill allows exceptions for animal testing in medical research related to human and animal diseases, provided certain conditions are met. The provisions regarding animal testing will take effect on October 1, 2025, and emphasize that testing methods should prioritize alternatives that reduce, refine, or replace animal use.

In addition to animal testing regulations, the bill mandates the gradual incorporation of biodiesel into diesel fuel sold at retail and used by state-operated vehicles, vessels, and construction equipment. Starting July 1, 2025, all diesel fuel must contain at least 5% biodiesel, increasing to 10% by July 1, 2027, and 20% by July 1, 2029. For state fleet vehicles, the biodiesel requirement is set at 5% by July 1, 2025, and 20% by July 1, 2027. The bill defines biodiesel as fuel derived from vegetable oils or animal fats that meet specific ASTM standards. The biodiesel provisions are effective immediately upon passage, while the animal testing provisions will take effect later in 2025.