The OEHHA of California government is intended to list the chemicals: Molybdenum trioxide & Indium tin oxide under the Safe Drinking Water and Toxic Enforcement Act of 1986 (Proposition 65) as they found to be meeting the characteristic of causing cancer. This action is being proposed based on the labor code listing mechanism, as these substances meeting its criteria of listing.

Usually, The International Agency for Research on Cancer (IARC) identifies whether a substance is carcinogenic & categorizes it as per the Health and Safety Code section 25249.8(a) incorporates California Labor Code section 6382(b)(1) into Proposition 65. The Labor Code section 6382(b)(1) refers to those substances which are carcinogenic to Human & animal as per IARC.

As per OEHHA’ determination the chemicals Molybdenum trioxide and indium tin oxide are meeting the requirements for listing as they are known to causing cancer in human & animals as per IARC’s report which is published on their website under the name “IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, Volume 118. Welding, Molybdenum Trioxide, and Indium Tin Oxide (IARC 2018)”. Based on the sufficient evidence of carcinogenicity in animals, IARC classified the two chemicals under “Group 2B (possibly carcinogenic to humans)”.

As usual, the OEHHA is open for public comments on the listing. The public comments period ends on 23rd November 2020. The OEHHA will consider the public comments about the rules provided by IARC for further investigations.

Reference link:

https://oehha.ca.gov/proposition-65/crnr/notice-intent-list-chemicals-labor-code-mechanism-molybdenum-trioxide-and-indium#_ftn2