Is your car killing you with benzene?

by admin / Jul 26, 2015 / 0 comments

An e-mail message that may have come into your inbox recently claims that dangerous levels of a cancer-causing chemical (benzene) are released from the plastic surfaces of automobile interiors. The e-mail recommends opening the vehicle's windows to remove the benzene before using the air conditioner.

Although benzene is linked to leukemia, very little research has looked at whether the interior surfaces of cars release dangerous amounts of benzene, and the information that is available does not support the e-mail's claims.
Let's break the message down and compare the claims with the facts:

Do not turn on A/C immediately as soon as you enter the car! Please open the windows after you enter your car and do not turn ON the air-conditioning immediately.
Car safety health tips
According to a research done, the car dashboard, sofa, air freshener emits Benzene, a Cancer causing toxin (carcinogen- take note of the heated plastic Smell in your car). In addition to causing cancer, it poisons your bones, causes anemia, and reduces white blood cells. Prolonged exposure will cause Leukemia, increasing the risk of cancer. May also cause miscarriage.

Acceptable Benzene level indoors is 50 mg per sq. ft.. A car parked indoors with the windows closed will contain 400-800 mg of Benzene. If parked outdoors under the sun at a temperature above 60 degrees F, the Benzene level goes up to 2000-4000 mg, 40 times the acceptable level ... and the people inside the car will inevitably inhale an excess amount of the toxins.

Car safety health tips
It is recommended that you open the windows and door to give time for the interior to air out before you enter. Benzene is a toxin that affects your kidney and liver, and is very difficult for your body to expel this toxic stuff.

Origins: This item about the dangers of benzene supposedly emitted by automobile components has been widely misunderstood. Many readers have come away from the article with the impression that it warns drivers not to use their cars' air conditioning because the A/C system itself is producing benzene, but what the article actually cautions against is the practice of turning on the air conditioning immediately upon entering an automobile. Motorists should instead, it says, roll down their windows in order to allow accumulated benzene fumes (allegedly emitted by other components, such as dashboards and upholstery) to vent from the car first before re-closing the windows and turning on the A/C.

How much truth is there to this warning? Evidence suggests an association between exposure to benzene and an excess risk of leukemia, as noted by the American Cancer Society (ACS):
A considerable number of human studies provide evidence linking benzene and cancer. Initially, increased risks of leukemia, chiefly AML, were reported among workers with high levels of benzene exposure in the chemical, shoemaking, and oil refining industries. More recently, studies have focused on workers with relatively lower exposure.

The human data are supported by animal studies. There is sufficient evidence for the carcinogenicity of benzene in experimental animals. Key animal studies support the finding of an excess risk of leukemia in humans from exposure to benzene by inhalation and ingestion. The details of these studies have been reviewed and found to support the association between benzene and cancer.
But do automobiles really produce potentially cancer-causing levels of benzene? No studies have yet documented that claim to be true. A 2001 study of commuter exposure (in both cars and buses) in Korean urban areas found some relationship between automobile use and exposure to benzene, but its observations differed from the warning quoted above in some significant areas:

The study found that traveling by automobile increased exposure to a number of deleterious compounds, including benzene, but the primary factor in this regard was the fuel used by the vehicles, not internal components such as dashboards.
Car safety health tips
The study found that benzene levels were higher in older cars than newer cars, which suggests that the primary factor in automobile benzene levels was not associated with the "new car smell" emitted by components such as dashboards and upholstery.

The study found that exposure levels were significantly higher during the winter months, which suggests that automobile air conditioning use is not a major factor in benzene exposure.

The Korean study itself did not establish a connection between commuter exposure to benzene and the onset of cancer.

A 2007 German study on "Toxicity of Parked Motor Vehicle Indoor Air" which specifically tested the health effects of emissions from one new and one three-year-old vehicle exposed to "parked in sunshine" conditions found "no apparent health hazard of parked motor vehicle indoor air":
Buters and his colleagues first collected molecules from the air inside a new car and a three-year-old vehicle of the same brand placed under 14,000 watts of light, where temperatures reached up to 150 degrees Fahrenheit. They next exposed these compounds to human, mouse and hamster cells grown in lab dishes. These are commonly used to test toxicity.

New car smell does not appear to be toxic, the scientists found. Air from the new car did cause a slight aggravation of the immune response that could affect people with allergies, but the same was not seen with the older vehicle.
(The German study also found the total amount of volatile organic compounds in a new car to be one-tenth the level claimed in the e-mail for benzene alone.)

The ACS similarly noted of this e-mail that:
We found no published studies that confirm the claims of this e-mail. Benzene levels that exceed recommendations for chronic workplace exposure have been observed in some moving cars, but these levels seem unlikely in properly maintained cars.
The e-mail did get one thing right, though: Upon returning to a closed car on warm days, you should open the windows for a minute or so rather than immediately turning on the air conditioning. The reason has nothing to do with benzene levels, however; rather, it's because when a car is parked in the sun with its windows rolled up, that condition can create a greenhouse effect which causes the interior of the vehicle to warm up to a temperature considerably higher than that of the outside air. Opening the windows for a few moments allows for the exchange of hot air from inside the vehicle with cooler air outside, speeding up the process of cooling off the car more than air conditioning alone would.

Claim: My car's manual says to roll down the windows to let out all the hot air before turning on the A/C. WHY?

Fact: On a sunny day, the temperature in a parked car can be more than 40 degrees (Fahrenheit) higher than the outside air. Opening the windows is the fastest way to exchange the hot interior air with the cooler outside air. Once that is done, the air conditioner can make the interior cooler than the outside air. The manual's recommendation is probably focused on passenger comfort rather than toxicology.
Car safety health tips

Claim: No wonder more folks are dying from cancer than ever before.

Fact: Actually, the age-adjusted cancer death rates in the United States have been decreasing for the past 2 decades.


Claim: Please do NOT turn on A/C as soon as you enter the car. Open the windows after you enter your car, and then turn ON the AC after a couple of minutes. Here's why: According to research, the car's dashboard, seats, a/c ducts in fact ALL of the plastic objects in your vehicle, emit Benzene, a Cancer causing toxin. A BIG CARCINOGEN... Prolonged exposure will cause Leukemia and increases the risk of some cancers.

Fact: Benzene is known to cause cancer, based on evidence from studies in both people and laboratory animals. The link between benzene and cancer has largely focused on leukemia and other cancers of blood cells. Rates of leukemia, particularly acute myeloid leukemia (AML), have been found to be higher in studies of workers exposed to high levels of benzene, such as those in the chemical, shoemaking, and oil refining industries.

Some studies have also suggested links to acute lymphocytic leukemia (ALL) in children and to chronic lymphocytic leukemia (CLL) and other blood-related cancers, such as multiple myeloma and non-Hodgkin lymphoma, in adults. However, the evidence is not as strong for these cancers.

A German study published in 2007 specifically researching the air inside parked cars did not find a hazard to human health. Their analysis detected some cancer-causing chemicals and others that are considered probable or possible carcinogens, but these chemicals were present at levels similar to those found in the air of buildings. Some chemicals that are similar to benzene were found, but benzene was not reported in the results of this study.


Claim: Acceptable Benzene level indoors is: 50mg per sq.ft. A car parked indoors, with windows closed, will contain 400-800 mg of Benzene. If parked outdoors, under the sun, at a temperature above 60 degrees F, the Benzene level goes up to 2000-4000 mg, 40 times the acceptable level. People who get into the car, keeping the windows closed, will inevitably inhale, in quick succession, excessive amounts of the BENZENE toxin.

Fact: The standard way to report levels of chemicals in air is mass per volume (for example, mg per cubic meter or cubic foot), not mass per area (mg per square foot). Although this is a technical detail, it suggests that the authors of this e-mail may have limited knowledge of the basic scientific principles of this topic.

Car safety health tips
Furthermore, United States regulations do not specify any single acceptable benzene level. The National Institute for Occupational Safety and Health (NIOSH) has a limit for short-term (15 minute) workplace exposure (3.2 mg per cubic meter) and for average workday exposure ( 0.32 mg per cubic meter). So, the benzene level stated in the e-mail (recalculated as mg per cubic meter) as acceptable is between the NIOSH levels for short-term and daily exposure.

Another blow against this claim comes from the German study previously mentioned. It measured the level of a whole group of chemicals in a new car and an older car "parked in sunshine." Levels were higher in the new car than the old one, but still 1/10 of the level claimed in the e-mail for benzene alone (and, benzene was not even among the more than 40 chemicals recognized in the study).

Several other studies -- from Germany, South Korea, and the United States -- have looked at benzene levels in moving cars. These levels have ranged from 0.013 to 0.560 mg per cubic meter. The high range of these reports exceeds the NIOSH chronic exposure limit, though in the US study, the highest level (0.045 mg per cubic meter) was found in a car the researchers described as malfunctioning.

The Upshot

We found no published studies that confirm the claims of this e-mail. Benzene levels that exceed recommendations for chronic workplace exposure have been observed in some moving cars, but these levels seem unlikely in properly maintained cars.( for more health tips visit )

Still, if you're concerned about benzene levels in cars (especially in cars with the engine running), there's no harm in opening the windows periodically or using an air-conditioner setting that circulates air from outside the vehicle.

And there are other steps people can take to reduce the amount of benzene to which they're exposed:

Stay away from cigarette smoke. If you are a smoker, try to quit. Cigarette smoke is a major source of benzene exposure.
If you are exposed on the job, talk to your employer about process changes (such as replacing the benzene with another solvent or making sure the benzene source is properly enclosed) or by using personal protective equipment. If needed, the Occupational Safety & Health Administration (OSHA) can provide more information or make an inspection.
Try to limit gasoline fumes by pumping gas carefully and choosing gas stations with vapor recovery systems that capture the fumes. Avoid skin contact with gasoline, which contains benzene.
Finally, use common sense around any chemicals that might contain benzene, like solvents, paints, and art supplies. Minimize or avoid exposure to their fumes, especially in unventilated spaces.