In January 2021, the US Environmental Protection Agency (EPA) issued five rules for the control of persistent, bioaccumulative, and toxic (PBT) substances, which set control requirements for DecaBDE, PIP (3:1), 2,4,6-TTBP, PCTP, and HCBD, totaling five substances.

The five PBT substance control requirements are as follows:

The Toxic Substances Control Act (TSCA) was enacted by the US Congress in 1976 and implemented by the US Environmental Protection Agency (EPA). The bill aims to comprehensively consider the impact of chemical substances circulating within the United States on the environment, economy, and society, and prevent "unreasonable risks" to human health and the environment. After multiple revisions, TSCA has become an important regulation for effectively managing chemical substances in the United States and a prerequisite for normal trade of products exported to the United States.

The restriction requirements in the rules for these five substances will be implemented in stages starting from March 8, 2021. Related companies need to pay attention to the compliance of their products in advance, otherwise they will be prohibited from going public.