Its comments came as environmental activist group As You Sow​​ filed a notice of intent to bring legal action vs Soylent alleging it breached California's Proposition 65 by failing to provide sufficient warning to consumers over lead and cadmium levels in Soylent 1.5.

Prop 65 requires manufacturers selling products in California to give clear warnings if their products expose consumers to any detectable amount of 800+ chemicals linked to cancer or reproductive toxicity.

Legalized blackmail?​

Despite its laudable aims, however, Prop 65 has proved controversial given that the vast majority of firms sued over alleged violations opt to settle - even if they are supremely confident in the safety of their products - because the burden of proof is on defendants to prove exposure levels are zero (or in the case of substances where safe harbor levels have been set, below a set threshold).

While this might seem eminently reasonable, critics of the law say many Prop 65 chemicals are present at trace levels in scores of foods without necessarily presenting a threat to human health, while safe harbor levels enshrined in Prop 65 are unrealistically low*.

The primary frustration for manufacturers, however, is that even if they can​ prove they are under Prop 65 safe harbor levels, the costs associated with defending yourself (hiring a toxicology expert, legal fees etc) will almost certainly exceed whatever amount plaintiffs demand in settlement, prompting some lawyers to argue that Prop 65 has turned into a form of “legalized blackmail​”.

‘Soylent is completely safe and nutritious’​

According to As You Sow, tests show that “one serving of Soylent​ can expose a consumer to lead concentrations 12-25 times higher”​ than the Prop 65 safe harbor level​​ for reproductive health, while cadmium concentrations are “at least 4 times greater​”.

However, Soylent insisted its products were “completely safe and nutritious”, ​adding in a blog post that: “Our testing is done by Covance, an independent third-party lab, using the ultra sensitive and precise method ICP-MS. Testing protocols are standardized by AOAC International. Lead in Soylent 1.5 is 0.009982ug/mL, less than 1/50th of the FDA requirements for infant food...​

"The FDA does not set cadmium limits for food, but even the highest cadmium levels we have seen in testing**, 21ug per serving, is thousands of times lower than the level of any observed effect in Proposition 65 toxicology data."​

It added: “We display a Proposition 65 warning to customers in both California and across the U.S. and Canada ​[the warning can be found at the bottom of the page if you shop on its website].We stand by the quality and safety of our product."​

It confirmed​​ on its website that “a ​recent quality assurance analysis conducted by an independent, third-party lab showed that the heavy metal content in the brown rice protein used in Soylent ​[1.5 powder] was above levels indicated in previous testing”, ​but said “these levels are in no way toxic”.​

It went on to refer to a recent FDA analysis​ ​revealing trace levels of lead and cadmium in hundreds of foods from spinach to canned peaches.

The name Soylent is an inside joke based on a ‘60s sci-fi novel adapted for the 1973 film Soylent Green in which the eponymous food supplement is made from human remains.

As You Sow: Soylent only added Prop 65 warning in June​

However, Andrew Behar, CEO of As You Sow, told FoodNavigator-USA that the lead levels in Soylent were “well over the legal limit”​.

He added: “Since Soylent is marketed as a meal replacement, users may be chronically exposed to lead and cadmium concentrations that exceed California's safe harbor level. We’ve worked with a few companies making protein powders and they just need to look at their ingredients and investigate.”​

He also claimed that Soylent had only added a Prop 65 warning to its website relatively recently (“We first noticed it in mid-June... several months after they first started selling Soylent​”), and that the format and wording used was "not fully compliant"​ with Prop 65.

He added: “The warnings are also not on the packaging, so if you buy it on Amazon, for example, there’s no warning.”​

We’re not in it for the money​

Asked whether this was just a money-making exercise – as many defense lawyers claim – he said: “We’re not in it for the money. We just want companies to reformulate their products or warn consumers appropriately if they are selling products containing toxic chemicals.”​

While he acknowledged that low levels of lead could occur naturally in the soil where rice and other food products are grown, he said the variation in lead levels between similar products often highlighted supply chain issues.

“We had a case with hot sauce where the lead levels were unusually high, and it turned out that the chili peppers were grown by the side of a road in Mexico where there was a lot of diesel traffic and this was causing the problem. The company switched suppliers and the problem was solved.”​

Attorney: 'It's basically extortion'​

However, Carol Brophy, an attorney at Sedgwick LLP, who has helped defend clients against scores of Prop 65 lawsuits (but is not involved in the Soylent case), said the As You Sow press release​​ re. Soylent was “alarmist​” and misleading, given that its figures appeared to be based on the assumption that people eat “nothing but Soylent every day, 365 days a year, forever​”.

From a toxicology perspective, she said, what mattered was a person’s estimated exposure to Prop 65 chemicals based on the “reasonably anticipated use of the product by the average consumer”, ​a position confirmed in March by California’s First District Court of Appeal in a case brought by Environmental Law Foundation vs Beech Nut Nutrition Corp***.

“If you average it out among users, meal replacements are typically eaten once every nine days.”​

Prop 65, she argued, had turned into an “extortion racket​” by a handful of “bounty-hunting​” law firms, adding: “They never back down so you have to go to full blown trial with experts and all the associated costs, so almost everyone settles​. It's basically extortion.”​

Handful of litigants bringing vast majority of Prop 65 cases​

According to the office of the California attorney general​​, As You Sow secured six Prop-65-related settlements in 2014. However, the most prolific litigants in this space are The Chandler Group Plaintiffs (245 settlements in 2014), The Center for Environmental Health (185 settlements in 2014), The Consumer Advocacy Group (92 settlements in 2014), and the Environmental Research Center (64 settlements in 2014), which have made millions out of these suits in recent years.

While some Prop 65 cases have real merit, many appeared to be blatant “revenue-generating exercises​” for the plaintiffs’ lawyers, claimed Stacy Don, an attorney at Roseville-based Toledo Don LLP.

“During a typical week there’s several meals I eat alone in front of the TV, weekday dinners mostly. Those were usually fast food, or frozen or canned. So I thought Soylent would be faster, easier, and healthier than what I had been doing before. I still eat out with friends several times a week, and the food at work is actually quite good.” Soylent customer

What is Soylent?​

While uncharitable observers have described Soylent as “only slightly more appealing than an IV bag​”, news​​ that it had secured $20m in VC funding in January made many industry commentators take the LA-based firm more seriously.

Space porridge jokes aside, the numbers don’t lie, said CEO Rob Rhinehart in a blog post​​ after the funding was announced, in which he claimed that Soylent was generating “millions of dollars per month in subscription revenues”.​

The company - which Rhinehart claimed was already profitable - would invest the $20m into long-term R&D and “significantly expanding​” its manufacturing and shipping capabilities to meet demand for its "neutral-tasting​" meals, which promise to deliver all the vitamins, minerals and macronutrients you need for less than $10 a day.

Early versions of the product required users to mix oil, powder and water; while later versions (Soylent 1.5​​) just required them to add water to a pouch of powder. The latest version is a ready-to-drink product that uses soy protein isolate instead of rice protein: Soylent 2.0​.​

*The Prop 65 safe harbor level for lead - at 0.5 µg per day - is 60 times lower than the average exposure permitted by the EPA in drinking water, and 6-12 times lower than the exposure from background levels in soil.

**See Soylent's certificate of analysis​ for Soylent 1.5.

***Environmental Law Foundation (ELF) v. Beech-Nut Nutrition Corp., 2015 B.L. 72035, (Cal. Ct. Ap., No. A139821, 3/17/15).