TABLE OF CONTENTS

There are a whole lot of ingredients that are in our foods, skincare, and haircare products that simply, should not be there. Benzene is one of them!  Benzene is an odourless chemical that has been proven to be harmful to human health, particularly over the long term.

In fact, research has shown that long-term exposure can cause cancers, particularly those of the blood. Its carcinogenic effects were recently brought to the mainstream with a recall by the Food and Drug Administration (FDA) in the USA, on October 18, 2022.  The recalls were for several shampoos of some well-known brands. The recall reportedly indicated that the brands of shampoos had a potentially elevated amount of the chemical. So, what is benzene? How harmful can it be to human health? Let’s discuss!

The Discussion

Benzene or Benzol is a known carcinogen that has its birth in 1825, by the well-known English scientist – Michael Faraday (TRIPP, 1925).  However, its carcinogenic effects on humans were first reported in the late 1920s with conclusive findings in animals in 1979 (Huff, 2007). The chemical, which is a colourless liquid, reportedly has a sweet aromatic odour (Agency for Toxic Substances and Disease Registry (ATSDR, 2007) and is highly inflammable.

Benzene can be found in the air, soil, and water supply via natural or industrial sources (Agency for Toxic Substances and Disease Registry (ATSDR, 2007).  However, crude oil is said to be the largest natural source of benzene (Public Health Fact Sheet, South Australia, 2007). Other natural sources of benzene include emissions from fires, gasoline products and even cigarette smoke (Smith, 2010).

Benzene can also be found in adhesives (i.e., cement, glues, and paste, etc.), cleaning products, paint products, deodorants, sunscreens, sanitizers, lotions, skincare products, haircare products such as shampoos as was recently reported.  As such, humans can become exposed to this carcinogenic ingredient in many ways, without even realizing it. However, some persons are even at greater risk of exposure due to their lines of work, such as those who work in petroleum refineries, oil pipelines and auto repair shops etc. (Smith, 2010).

In this article we will be exploring some of the questions surrounding benzene, this includes its carcinogenic effects upon exposure, the possibility of developing leukemia both in childhood and adulthood, particularly myeloid leukemia, how can one get exposed to this chemical, how it metabolizes in the body, what to do if you become exposed to this chemical as well as some of the products that this chemical can be found so that you can be on your guard.

You can read more on chemicals to examine or seriously avoid in these articles:

• • Oh No, not on my skin – Five (5) Skincare ingredients to carefully examine or just avoid!

  • The ‘pigly’ truth about nitrates and nitrites and four (4) deadly reasons to avoid them!

Explorations and Answers of the Chemical – Benzene!

1. What are the metabolism and carcinogenicity of benzene exposure?
2. Can benzene exposure cause leukemia in adults – especially myeloid leukemia?
3. Can benzene exposure cause childhood leukemia?
4. Other than the use of certain products, how else can I become exposed to benzene?
5. What are some of the long-term effects of benzene exposure?
6. What are some of the signs and symptoms of benzene exposure?
7. So, if I become exposed to Benzene, what can I do?

What are the Metabolism and Carcinogenicity of Benzene Exposure?

For benzene to become carcinogenic, it must be metabolized by the body (Ross, 2000; Snyder, 2004).  As such, research has shown that several benzene metabolites contribute to the creation of benzene toxicity (Synder and Hedli, 1996). Therefore, In the body, benzene is metabolized to varying reactive species such as benzene oxide, benzene diolepoxide, muconaldehydes etc. (Waidyanatha et. al. 2005). However, some of the more stable molecules are excreted by the body via the urine, this includes phenol, hydroquinone, catechol etc. (Waidyanatha S.et al. 2004).

Benzene is primarily metabolized in the liver and then transported to the bone marrow.  When this happens, it can cause the bone marrow to become what is called ‘depressed’ which results in the damaging of cellular macromolecules which then induce oxidative damage to the cells of the body (Synder and Hedli, 1996).  This is one of the main reasons many researchers have concluded its association with leukemia (leukemogenesis).    

Nonetheless, the effects of the different mechanisms that can lead to benzene toxicity are still not fully established as different mechanisms can contribute to the toxicities of the different metabolites of benzene (Synder and Hedli, 1996).  According to research, some of the metabolites can cause harmful effects on the body while most leave our body via our urine within forty-eight (48) hours of exposure (Public Health Fact Sheet, South Australia, 2007).

Therefore, continuous research is required to help in determining the specific combination of metabolism as well as how it targets the body, biologically.  This will help to provide a better understanding of how benzene is metabolized to the extent that it damages the bone marrow (Synder and Hedli, 1996).

Can Benzene exposure cause leukemia in adults – especially myeloid leukemia?

Benzene is considered one of the simplest forms of aromatic chemical with a great solvency profile.  However, growing research is exposing its cancer-causing effect. Its hazardous and possibly hematotoxin effects on humans were realized with its industrial use way back in 1897 (Smith, 2010).  Several cases of its toxic effects were investigated by the researcher, Santesson after his review of over nine (9) cases (Santesson, 1897).  Additional research on its toxic effects on the human body was confirmed by other researchers including Selling (1916) and Weiskotten (1920, 1916).  The findings of these studies led to some of the initial warnings of its use occupationally.

Benzene’s possible effects on the development of leukemia were investigated by Delore and Borgomano in 1928 (Delore and Borgomano, 1928).  Additional cases of its human exposure and leukemia, which is a disorder of the blood, were reportedly denoted within 30 years (the 1930s to 1960s) (Aksoy et al., 1971; Aksoy et al., 1972; Goldstein, 1988 and Vigliani and Saita, 1964).  

According to the research, the incidences of leukemia were mostly found in individuals who were exposed to the chemical via industrial means (persons who worked directly with the chemical). Additionally, persons who used benzene as a solvent as well as in glue such as a shoemaker were reporting higher incidences of this disease (Smith, 2010).  This was further confirmed by a study in Italy by Vigliani and his colleagues (Forni et al., 1971) as well as in Turkey (Aksoy et al. 1988, 1989). 

However, the increased risk of one developing leukemia due to exposure to benzene was manifested in 1977 when researchers found the first positive set of findings (Smith, 2010).  This was due to a study of workers in the Rubber Industry in the USA (Infante et al, 1977). The Rubber industry includes makers of cars and tyres etc.   The research concluded that workers in this industry have a fivefold increased risk of developing leukemia with a tenfold increase in deaths. 

It must be noted that the report specifically dealt with persons in this industry between the years 1940-1949.  Importantly, the form of leukemia that was reported as causing the deaths were myeloid and monocytic leukemia. Myeloid leukemia or acute myeloid leukemia is a cancer of the blood as well as the bone marrow. It is considered the most type of acute leukemia found in adults (cancer.gov). On the other hand, monocytic leukemia is a type of myeloid leukemia where most of the monocytes are in the marrow (cancer.gov).

A more recent study by Rinsky et al (2002), confirmed the findings of the previous research of earlier years, o the effects of developing leukemia from benzene exposure, especially over the long term (Rinsky et al., 2002; Rinsky et al., 1987).  Additionally, studies in China and Australia have also confirmed and expanded the findings of prior studies (Smith, 2010).

Importantly, the study in China showed excess risks of leukemia and death in workers of rubber hydrochloride, even when the exposure where at lower levels than were reported in prior studies (less than 10 ppm average and less than 40 ppm cumulative years) (Yin et al., 1987). Notably, research has shown that one can develop an increased risk of leukemia at exposure above 2 ppm – years, cumulatively (Glass et al., 2001; Glass et al., 2005).  As such, one’s risk will increase with even higher exposure.

Can Benzene exposure cause childhood leukemia?

While most of the previous studies on leukemia association with benzene were done with adults. There is growing research that has been investigating the risk of developing leukemia in childhood from benzene exposure.  One such study was conducted in France on a review of over 700 cases of acute leukemia.  The research concluded that most of the cases were significantly associated with persons who lived close to gas/petrol stations or worked with motor vehicle repair garages (Smith, 2010).  

Studies also show an increased risk of childhood leukemia via air pollution as well as from sources that emit benzene such as gas stations and when traversing in traffic (Smith, 2010).  Nonetheless, more research is recommended for studies in this area, especially as it relates to the environment benzene exposure.

Leukemia in children is said to usually start in utero of the mother due to genetic changes that occur in the blood (Greaves and Wiemels, 2003; McHale et. al., 2003, Wiemels, 2002).  Therefore, exposure to benzene by both prospective mothers and fathers may be an important consideration for the development of leukemia in childhood (McKinney et. al., 1991; van Steensel-Moll HA et al. 1985).

Other than the use of certain products, how else can I become exposed to Benzene?

All of us are exposed to benzene to a small extent, particularly daily.  This is due largely to the air we breathe which may be contaminated with benzene. However, some of the major sources of exposure are tobacco smoke, gas station emissions, exhaust from motor vehicles, industrial emissions, etc. (Agency for Toxic Substances and Disease Registry (atsdr.cdc.gov).  Benzene can enter our body through our lungs and skin (Agency for Toxic Substances and Disease Registry (atsdr.cdc.gov).

As such, you can become exposed to some of the products we use e.g., shampoos, glues, paints, detergents even furniture wax, which usually have this chemical as an ingredient.  However, reports indicate that industrial emissions accounts for about twenty (20%) percent of benzene exposure. However, this percentage was directed to the United States (Agency for Toxic Substances and Disease Registry (atsdr.cdc.gov).  

Also, people living in the city are said to be exposed to even higher levels of benzene than those who live in rural areas (Agency for Toxic Substances and Disease Registry (atsdr.cdc.gov). Surprisingly, reports contend that you may even be more exposed to this toxic substance in your home than when outdoors (Agency for Toxic Substances and Disease Registry (atsdr.cdc.gov).

We can also become exposed to benzene by the very foods we eat, including beverages and even water supply due to leaks from petroleum storage areas.  Benzene was also detected in some liquor and bottled water (Agency for Toxic Substances and Disease Registry (atsdr.cdc.gov).  The highest level of exposure though will be those persons who work in industries that manufacture or use benzene in their production processes, e.g., Petroleum refinery, coal, and rubber tyres, etc. Agency for Toxic Substances and Disease Registry (atsdr.cdc.gov).  

Therefore, it is important to note that benzene exposure occurs from many sources and to varying degrees. As such, we have to try and limit or reduce our total exposure to the lowest amount possible (Agency for Toxic Substances and Disease Registry (atsdr.cdc.gov).

What are some of the long-term effects of Benzene exposure?

While short-term exposure, especially at a minimum degree may not cause many chronic issues as per research, studies have shown that long-term exposure, particularly to high degrees is the main culprit.  According to reports, long-term exposure to benzene can cause cancer of the blood or what is called leukemia (Agency for Toxic Substances and Disease Registry (atsdr.cdc.gov).  

Research has shown that exposure in general, particularly over the longer term has been associated with a type of leukemia known as acute myeloid (AML). You can read more on myeloid Leukemia in #2 above.  Long-term exposure to benzene may also harm the reproductive organs, especially if it is inhaled at high levels (Agency for Toxic Substances and Disease Registry (atsdr.cdc.gov).

What are some of the signs and symptoms of Benzene exposure?

According to research, brief exposure of say 5-10 minutes to very high levels of benzene in the air (10,000 – 20,000 ppm) can cause death. However, lower levels of say 700-3,000 ppm (parts per million) may cause drowsiness, dizziness, the rapid beating of the heart, headaches, tremors, confusion, and even unconsciousness (Agency for Toxic Substances and Disease Registry (atsdr.cdc.gov).  These effects will diminish once you are no longer exposed to the chemical and begin to inhale fresh air.

Additionally, exposure to benzene via our food (consuming foods with it) can cause vomiting, irritation of the stomach, dizziness, sleepiness, convulsion, rapid beating of the heart to the extent of a coma, and the possibility of death (Agency for Toxic Substances and Disease Registry (atsdr.cdc.gov). Also, if benzene or related products come into contact with the skin, it can become irritated and cause sores in some cases.  Prolonged exposure to benzene can interrupt the immune system which can weaken it and thus cause you to become susceptible to frequent infections. 

However, if you experience all or some of these noted symptoms, please note that it does not necessarily mean that you have been exposed to benzene. But if you believe or know you have, based on your circumstance, please visit an emergency room immediately.  You can read more on what to do if you become exposed to this substance below, #7.

So, if I become exposed to Benzene, what can I do?

If you believe that you have been exposed to benzene, especially in large amounts, please seek medical attention right away.  Additionally, here are some other steps you can take if you are unable to visit an emergency room right away:

• If the exposure is by air, change your location and get fresh air.
• If it is via someone smoking, remove yourself from that space. This is one of the reasons it is not safe to smoke in your house, enclosed areas, or even near children.
• If the benzene has touched your clothing, remove the clothing immediately. In so doing, do not touch the areas that have the benzene or pull it over your head (as it can touch your skin). Instead, tear it or cut off the clothing so that it does not touch any other part of your body. Also, please ensure that you dispose of the clothing safely by putting it in a bag and discarding it, but not among other clothing.
• If the benzene has made contact with your skin, please wash the area thoroughly with soap and water.

Illustrative Summary

Here is an illustrative summary of the Exploration of Answers to the Chemical – Benzene!

Let’s Sum Up!

Benzene is a toxic chemical that is present in the very air we breathe due to its many sources. One major source of benzene is gas stations. Another major source is motor vehicle emissions.  Both short- and long-term exposure can affect the body negatively, as we are all unique.  However, long-term exposure reportedly can cause severe blood disorders such as cancers.

So, while we may not be able to reduce all our exposure, our safest bet is to keep our exposure to a minimum and seek medical attention if we have been exposed at small amounts and substantial levels.  Remember, to be mindful of what you eat, put on your skin, and breathe in, as that can impact your overall exposure. However, the more we know, the better it will be for us to navigate our lives, hence this article. It provides you with the knowledge and how to manage your exposure, at any level.

So, have you ever heard of benzene? Did you know that it was found in some major brands of popular shampoos just recently? Share it nuh!

You can read more on some ingredients to carefully examine or simply avoid by reading these posts:

• Oh No, not on my Skin – Five (5) Skincare ingredients to carefully examine or just avoid!

• The pigly truth about Nitrates and Nitrites and four (4) deadly reasons to avoid them!

References

• Aksoy M, Dincol K, Akgun T, Erdem S, Dincol G. Haematological effects of chronic benzene poisoning in 217 workers. Br J Ind Med. 1971; 28:296–302. [PubMed: 5557851].
• Aksoy, M. Benzene hematotoxicity. In: Aksoy, M., editor. Benzene Carcinogenicity. Boca Raton, FL: CRC Press; 1988. p. 59-112.
• Aksoy M. Hematotoxicity and carcinogenicity of benzene. Environ Health Perspect. 1989; 82:193–97. [PubMed: 2676498]
• Aksoy M, Dincol K, Erdem S, Akgun T, Dincol G. Details of blood changes in 32 patients with pancytopenia associated with long-term exposure to benzene. Br J Ind Med. 1972; 29:56–64. [PubMed: 5060246].
• Delore P, Borgomano C. Leucemie aigue au cours de l’intoxication benzenique: sur l’origine toxique de certaines leucemies aigues et leur relations avec les anemies graves. J Med Lyon. 1928; 9:227–33.
• Forni AM, Cappellini A, Pacifico E, Vigliani EC. Chromosome changes and their evolution in subjects with past exposure to benzene. Arch Environ Health. 1971; 23:385–91. [PubMed: 5133800].
• Goldstein BD. Benzene toxicity. Occup Med. 1988; 3:541–54. [PubMed: 3043738].
• Glass DC, Gray CN, Adams GG, Manuell RW, Bisby JA. Validation of exposure estimation for benzene in the Australian petroleum industry. Toxicol Ind Health. 2001; 17:113–27. [PubMed: 12479507].
• Glass DC, Gray CN, Jolley DJ, Gibbons C, Sim MR. Health Watch exposure estimates: Do they underestimate benzene exposure? Chem Biol Interact. 2005; 153–54:23–32.
• Greaves MF, Wiemels J. Origins of chromosome translocations in childhood leukaemia. Nat Rev Cancer. 2003; 3:639–49. [PubMed: 12951583].
• Huff J. Benzene-induced cancers: abridged history and occupational health impact. Int J Occup Environ Health. 2007 Apr-Jun;13(2):213-21. doi: 10.1179/oeh.2007.13.2.213. PMID: 17718179; PMCID: PMC3363002.
• Infante PF, Rinsky RA, Wagoner JK, Young RJ. Leukaemia in benzene workers. Lancet. 1977; 2:76–78. [PubMed: 69157].
• McHale CM, Wiemels JL, Zhang L, Ma X, Buffler PA, et al. Prenatal origin of childhood acute myeloid leukemias harboring chromosomal rearrangements t(15;17) and inv(16). Blood. 2003; 101:4640–41. [PubMed: 12756163].
• McKinney PA, Alexander FE, Cartwright RA, Parker L. Parental occupations of children with leukaemia in west Cumbria, north Humberside, and Gateshead. Br Med J. 1991; 302:681–87. [PubMed: 2021741].
• Rinsky RA, Hornung RW, Silver SR, Tseng CY. Benzene exposure and hematopoietic mortality: a long-term epidemiologic risk assessment. Am J Ind Med. 2002; 42:474–80. [PubMed: 12439870].
• Rinsky RA, Smith AB, Hornung R, Filloon TG, Young RJ, et al. Benzene and leukemia. An epidemiologic risk assessment. N Engl J Med. 1987; 316:1044–50. [PubMed: 3561457].
• Ross D. The role of metabolism and specific metabolites in benzene-induced toxicity: evidence and issues. J Toxicol Environ Health A. 2000; 61:357–72. [PubMed: 11086940].
• Santesson GG. Uber chronische Vergiftungen mit steinkohlen Benzin. Vier todes falle. Arch Hyg. 1897; 31:336–76.
• Selling L. Benzol as a leucotoxin. Studies on the degeneration and regeneration of the blood and haematopoietic organs. Johns Hopkins Hosp Rep. 1916; 17:83–148.
• Smith MT. Advances in understanding benzene health effects and susceptibility. Annu Rev Public Health. 2010;31:133-48 2 p following 148. doi: 10.1146/annurev.publhealth.012809.103646. PMID: 20070208; PMCID: PMC4360999.
• Snyder R, Hedli CC. An overview of benzene metabolism. Environ Health Perspect. 1996 Dec;104 Suppl 6(Suppl 6):1165-71. doi: 10.1289/ehp.961041165. PMID: 9118888; PMCID: PMC1469747.
• Snyder R. Xenobiotic metabolism and the mechanism(s) of benzene toxicity. Drug Metab Rev. 2004; 36:531–47. [PubMed: 15554234]
• TRIPP, E. The Discovery of Benzene. Nature 115, 909 (1925). https://doi.org/10.1038/115909a0.
• Vigliani EC, Saita G. Benzene and leukemia. N Engl J Med. 1964; 271:872–76. [PubMed: 14185112].
• van Steensel-Moll HA, Valkenburg HA, van Zanen GE. Childhood leukemia and parental occupation. A register-based case-control study. Am J Epidemiol. 1985; 121:216–24. [PubMed: 3860001]
• Waidyanatha S.et al. 2004. Rapid determination of six urinary benzene metabolites in occupationally exposed and unexposed subjects. Anal. Biochem., 327, 184 – 199.
• Waidyanatha S. et al.  2005. Investigation of cysteinyl protein adducts of benzene diolepoxide .  Chem. Biol. Interact., 153,– 154, 261– 266.
• Weiskotten HG, Gibbs GBF, Boggs EO, Templeton ER. The action of benzol. VI Benzol vapor leucopenia (rabbit). J Med Res. 1920; 41:425–38. [PubMed: 19972514].
• Weiskotten HG, Shwartz SC, Steinsland HS. The action of benzol on blood and blood forming tissues. J Med Res. 1916; 35:63–69. [PubMed: 19972322].
• Wiemels JL, Xiao Z, Buffler PA, Maia AT, Ma X, et al. In utero origin of t(8;21) AML1-ETO translocations in childhood acute myeloid leukemia. Blood. 2002; 99:3801–5. [PubMed: 11986239].
• Yin SN, Li Q, Liu Y, Tian F, Du C, Jin C. Occupational exposure to benzene in China. Br J Ind Med. 1987; 44:192–95. [PubMed: 3828244].