The chemical reaction that killed the manager of a Buffalo Wings restaurant in Massachusetts yesterday is arguably the most fundamental of all chemical reactions: Neutralization – the combination of an acid with a base to form a salt. If you’ve taken chem lab chances are you ran this experiment: The neutralization of hydrochloric acid by sodium hydroxide or vice versa:
NaOH (base) + HCl (acid) ——-> NaCl (salt) + H2O (water)
Reaction 1. A typical neutralization experiment. pH paper (aka litmus paper) measures the acidity or basicity of a solution.
Photo: Fine Art America
Unfortunately for Ryan Baldera, the restaurant manager, the neutralization experiment he inadvertently carried out by pouring bleach (strongly basic) onto a floor covered with an acidic residue (left by another cleaning product) not only formed salt and water, but also chlorine – a deadly green gas, which was used as a chemical weapon in World War I. Although the reaction of bleach with acid is fundamentally the same as that with sodium hydroxide, there is one difference and it is deadly: After the neutralization takes place another reaction – the recombination of Cl+1 and Cl-1 to form Cl2 (chlorine gas) takes place. (1)
Reaction 2. Bleach (sodium hypochlorite) reacts with hydrochloric acid to form salt, water, and chlorine gas. The upward-pointing arrow indicates that a gas has been formed.
News reports indicated that another cleaner called Scale Kleen, a mixture of citric acid and aluminum chloride, had been previously used on the floor. These chemicals, both solids, left a film on the floor, similar to the white residue you see on streets (road salt) after a snowstorm. (2) When Baldera poured the bleach solution onto the floor it reacted with the acidic film, generating chlorine, as shown above in Reaction 2.
Presumably, Mr. Baldera did not either did not know that Scale Kleen had been used or did not understand the consequences of what he did. He did, however, make one serious mistake and it was this error that killed him. According to news reports, Baldera saw a green gas bubbling off the floor, grabbed a squeegee, and tried to push it out of the store, putting his head near the chlorine that was foaming up from the floor. Even a single whiff of chlorine (in sufficient quantity) is sufficient to cause irreversible and fatal lung damage. Had he instead evacuated the restaurant and called 911 there is a good chance that this tragedy would not have occurred.
Bleach is an excellent chemical for removing stains and killing germs, but it is chemically reactive. And when it does react it will almost always produce chlorine. Here are some other chemicals that are found in homes and also react with bleach:
- Ammonia reacts to form another toxic gas called chloramine (NH2Cl).
- Vinegar (dilute acetic acid) reacts with bleach just like hydrochloric acid, liberating chlorine gas.
- Alcohol reacts with bleach to form a mixture of dangerous gases, for example, chloroform and hydrogen chloride.
The take-home message from this awful accident is that anytime you are using bleach and notice a color change (especially green), gas being formed, or a swimming pool smell, leave the area immediately and call 911. Hazmat crews know exactly what to do. So do chemists.
(1) Although it might seem odd to see written as Cl+ when Cl– is far more familiar, the chlorine atom in bleach is, in fact, is in the +1 oxidation state. This reaction can be seen as taking place in two “discrete” steps – neutralization followed by chlorine formation.
(2) It’s a bit more complicated. Scale Kleen consists of citric acid, (which itself can react with bleach) and aluminum chloride, which reacts with water to form HCl and aluminum hydroxide. So, the residue on the floor would have been an acidic mixture of citric acid, aluminum hydroxide and whatever HCl might have been trapped in the solid.
By Josh Bloom
Dr. Josh Bloom, the Director of Chemical and Pharmaceutical Science, comes from the world of drug discovery, where he did research for more than 20 years. The field of drug discovery involves chemistry, biochemistry, toxicology, and pharmacology – skills that he has used to write on a wide variety of topics since he joined ACSH in 2010. One of the topics he has tackled is the so-called “opioid crisis.” He is now recognized as an expert in this area and was the first journalist to write a nationally published opinion piece about the unintended consequences of a governmental crackdown on prescription pain medications (New York Post, 2013). Since that time he has published more than 20 op-eds in regional and national newspapers on different aspects of the crisis. In that same year, he testified at an FDA hearing, where he noted that fentanyl was the real danger, something that would be proven years later. At that time almost no one had heard of the drug.
He was also the first writer (2016) to study, dissect and ultimately debunk the manipulated statistics used by the CDC to justify its recommendations for opioid prescribing, which have resulted in Draconian requirements for prescribing pain medications as well as government-mandated, involuntary tapering of patients receiving opioid treatment, both of which have caused great harm and needless suffering to chronic pain patients. His 2016 article, “Six Charts Designed to Confuse You,” is the seminal work on CDC deception and has been adopted by patient advocacy groups and individuals and has been sent to governors and state legislatures.
Dr. Bloom earned his Ph.D. in organic chemistry from the University of Virginia, followed by postdoctoral training at the University of Pennsylvania. His career in drug discovery research began at Lederle Laboratories, which was acquired by Wyeth in 1994, which itself was acquired by Pfizer in 2009. During this time he participated in research in a number of therapeutic areas, including diabetes and obesity, antibiotics, HIV/AIDS, hepatitis C, and oncology. His group discovered the novel antibiotic Tygacil®, which was approved by the FDA for use against resistant bacterial infections in 2005. He is the author of 25 patents, and 35 academic papers, including a chapter on new therapies for hepatitis C in Burger’s Medicinal Chemistry, Drug Discovery and Development, 7th Edition (Wiley, 2010), and has given numerous invited lectures about how the pharmaceutical industry really works.
Dr. Bloom joined the American Council on Science and Health in 2010 as ACSH’s Director of Chemical and Pharmaceutical Sciences, and has since published more than 60 op-eds in numerous periodicals, including The Wall Street Journal, Forbes, New Scientist, The New York Post, National Review Online, The Boston Herald, and The Chicago Tribune, and given numerous radio and television interview on topics related to drugs and chemicals. In 2014, Dr. Bloom was invited to become a featured writer for the site Science 2.0, where he wrote more 75 pieces on a broad range of topics.