A while ago, while there was a scare about elevated lead levels in licorice, which led to a recall that worried lots of parents. The level in the candy was .18 ppm: http://www.foodsafetynews.com/2012/08/black-licorice-recalle...

At that time, I tried to understand how much of a risk this actually presented. My conclusion was no, it did not present any significant risk to anyone. In fact, this elevated level was less than half the amount that the EPA considered safe a few years earlier. And the EPA had changed it's standard from the previous presumed to be safe level of .5 ppm to .1 ppm not because of new evidence of risk, but because of a change in philosophy: http://www.fda.gov/RegulatoryInformation/Guidances/ucm077904...

This recommended maximum level of 0.1 ppm for lead in candy
likely to be consumed frequently by small children is
consistent with the FDA's longstanding goal of reducing
lead levels in the food supply to reduce consumers' lead
exposure to the lowest level that can be practicably
obtained.

Previously, they had set the standard based on the level of exposure shown to cause harm, divided by a safety factor (usually some power of 10) to account for uncertainty and differences in individuals: http://www.epa.gov/iris/rfd.htm

So the furor over licorice was not because there was any new evidence that the level was unsafe, or even that there was greater uncertainty of the safety, but because similar products were tested and found to have lower levels. In one sense, this seems reasonable: lead is very bad for you, so we don't want any of it in our food. But if the lead exposure from food is much less than the environmental lead exposure from other sources, it's hard to justify going to extremes to remove the remaining tiny fraction.

With this in mind, the tested level of lead in Soylent was .01 ppm. The California "safe harbor" level for lead is .5 µg per day. Thus if you ate 50g of Soylent, you would exceed the level at which California requires a warning.

For comparison, the EPA action level for lead in drinking water is .015 ppm, and the EPA says that if the level is less than this you should not worry: http://www.cdc.gov/nceh/lead/tips/water.htm

Thus if you drank 35g of the water that the EPA considers safe (about 2.5 tablespoons) you'd also be exceeding the threshold for which the State of California requires a warning label. In fairness, the level of lead in most drinking water is significantly less than the EPA action level. The US average appears to be about .003 ppm, thus you would on average have to consume (by weight) 3 times as much water as Soylent to receive the same dose of lead: http://www.who.int/water_sanitation_health/dwq/chemicals/lea...

I'm guessing that 3:1 is about the ratio at why Soylent is typically made? If so, it would seem fair to say that if you are using average US tap water, you are more at risk from lead poisoning from the water with which the Soylent is made than from the Soylent itself, for which they are being sued for not making their warning sufficiently prominent.

If this wasn't enough, that last link from the World Health Organization also estimates that an adult gets about 4 µg of lead per day just from breathing. To equal this amount from Soylent, you'd have consume 400g (1 lb) of Soylent per day. Since Soylent is packaged in 459g packages designed for 3 meals, it would be false to claim that you are getting more lead from the air than you do from the Soylent. But if you only ate two meals of Soylent per day, you'd be getting more from the air than from the Soylent.

So despite being a strong believer in food safety, as a former owner of a failed California food business (whose failure was in considerable part due our inability to manage the with regulatory requirements) I applaud Soylent for fighting back here.