Public outrage is mounting in China over allegations that a major state-owned food company has been cutting costs by using the same tankers to carry fuel and cooking oil – without cleaning them in between.
Public outrage is mounting in China over allegations that a major state-owned food company has been cutting costs by using the same tankers to carry fuel and cooking oil – without cleaning them in between.
The scandal, which implicates China’s largest grain storage and transport company Sinograin, and private conglomerate Hopefull Grain and Oil Group, has raised concerns of food contamination in a country rocked in recent decades by a string of food and drug safety scares – and evoked harsh criticism from Chinese state media.
It was an “open secret” in the transport industry that the tankers were doing double duty, according to a report in the state-linked outlet Beijing News last week, which alleged that trucks carrying certain fuel or chemical liquids were also used to transport edible liquids such as cooking oil, syrup and soybean oil, without proper cleaning procedures.
This is obviously not good, but I don't have great intuition.
If I have a mug full of gasoline (or worse, diesel or something cruder), and reuse that for coffee, I can imagine that being bad. But a tanker truck is humongous, and the contamination would, I imagine (???), scale roughly like a surface area-to-volume kind of thing, meaning that contamination for a huge container should be substantially "better" than my coffee example. (Perhaps this scaling law is a bogus assumption though?)
Of course it is still bad, gross, and probably dangerous...
The additives and chemicals in fuel are straight up cancerous. Your coffee in this example, would now come with a hint of crippling disabilities for your children.
Your supposition about surface area is correct but with contaminants this powerful it's not really valid.
There's also no telling how "empty" this thing actually gets before they fill it back up. If they're being this reckless, there's no reason to think they're fully draining the tanker.
Yup, and that's why they got away with it without anyone noticing. Eating that oil your whole life is probably not good for you though, because fuel chemicals can be pretty nasty. They say there's no safe level of a carcinogen.
Put your money where your mouth is. Take an old gasoline can and fill it with cooking oil then feed it to your family until it's empty. Record the results. You won't though.
My question was an honest scaling law question. Of course this is bad. Which is what I said.
My question is how bad, which is a legitimate question, and is not in any way saying these are defensible actions. They are not.
If you fill a thimble with diesel, drain it, and then fill it with water, that's gonna be super gross --- the diesel will probably form a thin layer on the thimble which is then diluted with a thimble full of water. Super gross. But by the time you get to a fuel can, the thin layer of diesel on the can is now diluted by a can of water. Because surface area scale like length squared but volume like length cubed, this is a better situation (for a given amount of water). Now when this is scaled up further, the diesel gets increasingly diluted. This is the root of my question, it's not saying that we should accept this or that it's good, I'm just curious.
If a cup has a few drops of water after you pour it out,
Say a drop is 0.05ml (20drop/mL is rule of thumb for chemistry). Say your glass cup holds 16oz (mine does), that's 473mL.
(4*0.05mL / 473mL) *100 = 0.04228% of the original concentration. Now scale that volume up. That ratio is going to be much smaller, since you're right about volume vs surface area.
5ppb is the cutoff for benzene in stunning water in Oregon apparently. EPA says 5ug/L.
5ppb is apparently 0.0000005%. That's about 84,000x higher than the cutoff for that one potential contaminant.
Given how small the minimum acceptable level is for many chemicals in gasoline or fuel... Yeah I bet it would increase cancer rates in a statistically significant way.
So 84,000 for a glass assuming 100% of the fluid is benzene (unless I misunderstood your calculation). Benzene concentration is about 1% of gasoline, and a tanker is about 20,000L, or ~40,000x more than a cup. Cube root of 40,000 is about 34 (cube root for the surface to volume factor). 34*100 is 3400, which is about 25x off from the 84,000 reduction required to be "safe." So it's roughly 25x worse than the Oregon cutoff (but seemingly within EPA limits, which appears to be ~1000x less stringent [!!!]). Unless I made some errors or misunderstood.
In any event I'll try to source my cooking oil from uncontaminated trucks!
(As an aside, thanks for taking my question seriously and putting thought into an answer, unlike some of the other more "colorful" responses!)
Test it out bro. Since you believe the impact of putting gasoline in food is so contentious. It's funny how you still deflect by implying it was "a thimbleful" when you have no idea how much it was or how dangerous it is.
...scaling laws. They are best illustrated with different sized items. Like a thimble, a coffee cup, or an oil tanker, all representing volumes of different orders of magnitude.
Stop, an empty tanker truck can have a huge amount of fuel in it. You do know that fuel has a lot of impurities right? If you don't believe me just pull up some pictures of fuel tanks on cars being opened. They can be caked with sediment and heavy metals at the bottom even after a few years.
A simple, "your scaling argument doesn't really apply since the amount of residue left behind scales with the volume, not area" would have sufficed.
Gasoline is a pretty powerful solvent; would residue left behind that doesn't come off from gasoline be liberated by cooking oil? It's an honest question.
And I sure hope the regulatory agencies and shipping companies in my country do a better job than in China. This sort of thing is terrifying; I'm just curious as to an emotionless analysis of how bad this likely is. What concentration of benzene is acceptable? "None" would be best but we already breathe it. Would contaminated cooking oil likely be equivalent to...inhaling once at a gas station? A wet martini with diesel instead of vermouth?
When the cooking oil is heated, the distillate contamination will flash off, leaving a nice clean cooking oil.
If distillate is slightly contaminated with with cooking oil, probably not so bad that engines burning it can't deal with the slightly differing heat rate and specific gravity of the new mixture.
I don't even feel like I should tell you why you're wrong, but here we go.
You assume that the fuel oil is more volatile then cooking temperatures, but what fuel oil? Diesel? Diesel has a boiling temperature between 160c and 360c(diesel varries because there are different compositions and blends). Deep fry is between 160c and 190c. That assumes we're deep frying. Plenty of ways to use cooking oil without heating to those temperatures.
Also assumes that there's nothing else in the fuel oil. Plenty of additives that might not boil off or if they do, be toxic if inhaled. I have of stories of transformer oil being used for deep frying.
Depends if it's light distillate, or, like, coal tar.
Butane -> cooking oil without washing would be fine, by the standard of if I'd still use the oil. I'd be more worried about leaching from the metal or plastic of the tank.