Metallic Particles Found in E-Cigs Are Below USP Limits

This article is part 3 of the Top 20 Rebuttals to Win an E-Cigarette Debate


Nanoparticles in E-CigsOne of the more recent studies involving electronic cigarettes came out of the University of California, Riverside. Published this past March in the scientific journal PLOS One was a research article about the contents of e-cigarette vapor. In a controversial and widely publicized discovery, the scientists found aerosol from one “mini” e-cig brand tested contained trace amounts of metallic particles.


However, the manner in the which the findings were presented was very misleading. Readers are lead to believe the metallic particles were found in sufficient enough quantities to cause harm to not only the vaper but those around him.


Key Points


  • Metallic particles found in e-cigs are comparable to those in nicotine inhalers.
  • Levels found were below maximum USP daily limits for inhalation products.
  • Trace metals are found in food and Earth's atmosphere as well.
  • E-cigarettes comply with federal safety standards and are not a health risk.


Study Analysis


The study compared levels of eleven elements found with those of tobacco cigarettes, finding nine were in higher concentrations in the cartomizers. What it didn't tell us was that the levels detected in the vapor were both on par with those of FDA approved nicotine inhalers. It also failed to inform that the concentrations were below USP standards for maximum allowable daily exposure in inhalation medications.


Dr. Michael Siegel presented the case perfectly in two blog posts shortly following the study's release. In one post he compared levels found in the study to those found in Nicorette inhalers.


According to the study, 10 puffs from the electronic cigarettes used contained .005 micrograms of nickel. Dr. Siegel noted that the aerosol in the Nicorette inhaler had .013 micrograms of nickel in the equivalent puffs. That's almost three times more than what was found in e-cig vapor.


More importantly, Siegel noted that levels of metallic particles in electronic cigarette vapor were also below maximum USP standards for metals in inhalation drug products. Thanks to Bill Godshall, Executive Director of Smokefree PA, we have the USP maximum daily inhalation dose in micrograms of lead, copper, chromium and nickel as follows:


  • Lead: 5mcg
  • Copper: 70mcg
  • Chromium: 25mcg
  • Nickel: 1.5mcg


Using the UC Riverside study results, we can deduct that a pack-a-day smoker would vape around 200 puffs per day, for a daily intake of 20 times the amount of each metal reported. Still, daily inhalation would come nowhere close to maximum USP limits as shown below.


  • Lead: 0.34mcg
  • Copper: 4.06mcg
  • Chromium: 0.14mcg
  • Nickel: 0.1mcg


While we only have maximum allowable limits for four of the metallic particles discussed in the study, the levels detected in the e-cig in question are significantly lower than USP standards. Nothing here would suggest any risk to using an electronic cigarette.


What Exactly is USP?


USP stands for The United States Pharmacopeial Convention and is a nonprofit scientific organization that sets quality standards for prescription, over-the-counter medications, dietary supplements and food ingredients. While it does not have authority to regulate products, it does provide an extra blanket of comfort for consumers.


USP standards are then used by both regulatory agencies and manufacturers to ensure that products contain the appropriate ingredients, as well as amount, quality, purity, and consistency. Prescription and OTC drugs sold in the United states are required by federal law to meet these standards.


The Truth About Metallic Particles in E-Cigs


This is an excerpt from a comment left on Dr. Siegel's blog:


Is it correct that whatever ‘trace metals' are in tobacco have come from the soil? Is it correct that whatever ‘trace metals' are in ecig liquid have come from the soil? Is it correct that whatever ‘trace metal' which are in nicotine patches have come from the soil? If the answer to those questions is, “Yes”, then it follows that those ‘trace metals' must be in almost everything that we eat. Not only that, but they must also be in the particulates which are released during cooking and which we detect as ‘aroma'. Further, such ‘trace metals' must be in the atmosphere, since they are so small that they can be part of floating debris in the atmosphere.


The trace metallic particles found in the one brand of electronic cigarette may have possibly come from the very soil that produces tobacco. The fact is that they may be found in many of the foods we eat and the air we breathe. The USP has simply set safety standards to limit our consumption of them.


Electronic cigarettes, at least according to the study findings, have safe levels for each of the metals in question that the USP sets quality standards for. And while it may be true that e-cigs contain trace amounts of said metals, they are still in compliance with federal safety standards and should therefore cause no alarm to health officials or the general public.