Someone else on r/Soylent laid out the numbers: Soylent 1.5 self-reported levels: Soylent is over the Prop65 safe harbor limits for cadmium and lead MADL and slightly over the lead NSRL, which means they must include a warning. My box of Soylent 1.5 does have a warning for children and pregnant women, but does not have a warning about carcinogens... probably because I don't live in California. Soylent claims they include the necessary warning for California, so I'm not sure exactly what they are being legally threatened about. sidenote... Prop 65 limits appear to be very conservative: California Prop 65 NSRL (No Significant Risk Levels) for carcinogens and MADL (Maximum Allowable Dose Levels) for chemicals causing reproductive toxicity:
(http://oehha.ca.gov/prop65/pdf/safeharbor081513.pdf) Cadmium: NSRL: 0.05 (inhalation) ; MADL: 4.1µg/day
Lead: NSRL: 15µg/day ; MADL: 0.5µg/day
(https://faq.soylent.com/hc/en-us/articles/204197379-California-Proposition-65) Cadmium: 21.39µg/500ml = 85.56µg/day
Lead: 4.99µg/500ml = 19.96µg/day "a person exposed to the chemical at the NSRL for 70 years would not have more than a "one in 100,000" chance of developing cancer as a result of that exposure"
(http://oehha.ca.gov/prop65/background/p65plain.html) MADL "is determined by identifying the level of exposure that has been shown to not pose any harm to humans or laboratory animals" then that level is "divided by 1,000 in order to provide an ample margin of safety"