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Study Reveals Car Interiors Giving Off Toxic Fumes

Chemicals Released from Indoor Auto Parts Contribute to
"New Car Smell" and Serious Health Concerns for Drivers & Passengers


Updated: May 2024

Worst Picks: Nissan Versa, Chevy Aveo, Scion xB 5dr, Kia Rio

Best Picks: Chevy Cobalt, Chrysler PT Cruiser, Honda Odyssey, Volvo V50



Back in 2007, the Ecology Center released the first-ever consumer guide to toxic chemicals in cars at healthycar.org. Over 200 of the most popular 2006- and 2007-model vehicles in the U.S. were tested for chemicals that off-gas from indoor auto parts such as the steering wheel, dashboard, armrests and seats. These chemicals become part of the air we breathe contributing to "new car smell" and a variety of acute and long-term health concerns. Since the average American spends more than 1.5 hours in a car every day, toxic chemical exposure inside vehicles is a major source of potential indoor air pollution.

The good news is that some cars are better than others. Toxic chemicals are not required to make indoor auto parts, and some manufacturers have begun to phase them out. Chemicals of primary concern include: bromine (associated with brominated flame retardants); chlorine (indicating the presence of polyvinyl chloride, or PVC and plasticizers); lead; and heavy metals. Such chemicals have been linked to a wide range of health problems such as allergies, birth defects, impaired learning, liver toxicity, and cancer.

Altough this has been an ongoing concern for many years now, not much has been done to address the problem. A new study (scroll down to bottom of page) warns that flame retardant materials that are required in all new vehicle interiors increase cancer risks!

This is old news, but the basic issue is still as relevant today as it was when this initial study was done.

Following are the 10 best and 10 worst of the cars that were tested back in 2007.

Chevrolet had the distinction of both best and worst pick in our samples, with the Cobalt scoring first and Silverado truck scoring last. Brands that fared well included Volvo and Honda/Acura, both with two models in the top ten. Kia/Hyundai joined Chevy with three entries in the worst ten.

"Our findings show that it is not necessary to use toxic chemicals when making indoor auto parts," said Jeff Gearhart, the Ecology Center Clean Car Campaign Director. "There is no excuse for manufacturers not to replace these hazardous chemicals with safe alternatives immediately."

To sample the vehicles, experts at the Ecology Center used a portable X-Ray Fluorescence (XRF) device, which identifies the elemental composition of any material in less than 60 seconds. In each vehicle 15 different components were sampled including: steering wheel, shift knob, armrest/center console, dashboard, headliner, carpet, seat front, seat back, seat base, hard door trim, soft door trim, body sealer, wiring, window seal and wheel weights. Components sampled were those most likely to be touched or otherwise contribute to human exposure.

While there are numerous substances in vehicles that can lead to health and environmental problems, HealthyCar.org selected those with known toxicity, persistence, and tendency to build up in people and the environment. These chemicals included:

Bromine: Associated with the use of brominated flame retardants, BFRs are added to plastics in order to impart fire resistance, but they are released into the environment over the life of the vehicle. Heat and UV-ray exposure in cars can accelerate the breakdown of these chemicals and possibly increase their toxicity. Some BFRs have been associated with thyroid problems, learning and memory impairment, decreased fertility, behavioral changes, and other health problems.

Chlorine: Associated with the use of polyvinyl chloride, PVC is a widely used type of plastic that is of concern to the environment and public health during all phases of its life cycle. PVC contains chemicals called phthalates, some of which have been associated with decreased fertility, pre-term deliveries, and damage to the liver, testes, thyroid, ovaries, kidneys, and blood. There is also evidence that phthalates can pass from mothers to babies through the placenta and through breast milk.

Lead: Lead is sometimes used as an additive in automotive plastics. Exposure can lead to a number of potential health effects including brain damage, and problems with the kidneys, blood, nerves, and reproductive system. It can also cause learning and behavioral problems.

Other: Other chemicals tested as part of healthycar.org include antimony, arsenic, chromium, cobalt, copper, mercury, nickel and tin. The substances in this category are allergens, carcinogens, or cause other adverse health impacts depending on the concentrations and exposure levels.

The same chemicals that cause human health issues can also cause problems in the environment. When vehicles are discarded at the end of their life, the majority of plastic and other non-metallic parts are shredded and put in landfills or burned in incinerators. When discarded in landfills, harmful chemicals contained in vehicle plastics can leach out and contaminate soil and water. When incinerated, toxic chemicals are dispersed throughout the atmosphere.



Is Benzene from Car Interior Plastics Harmful?

Emails have been circulating that claim the plastics used in car interiors give off harmful levels of benzene. The email warns readers to roll down their windows when they first get into their cars, and to avoid using their air conditioner until the dangerous vapors are allowed to dissipate and escape. The email goes on to say that benzene vapors can rise to dangerous levels if a vehicle is left parked in the hot sun with the windows up.

Truth or fiction? Benzene is an ingredient in automotive interior plastics. And yes, a small amount of benzene will outgas from the plastics over time, especially from newer vehicles and especially on hot days. The fumes from plastics in new cars can be 8 to 10 times higher than those in vehicles that are several years old. However, the amount of benzene given off does not appear to pose a significant health risk.

According to Scopes, the amount of benzene measured by researchers was only a fraction of that claimed in the email. Researchers found benzene concentrations from .013 mg to .56 mg per cubic meter, while the email claimed some vehicles were giving off as much as 400 mg to 4,000 mg per square foot.

What's more, there are no toxicology studies that show any observable toxic effects on people or animals at concentrations typically found in new or used vehicles.


Guide to Toxic Chemicals in Cars Helps Consumers Avoid "New Car Smell" As Major Source of Indoor Air Pollution

Best Picks: Honda Civic, Toyota Prius, Honda CR-Z

healthycar best worst 2012 cars toxic fumes

Worst Picks: Mitsubishi Outlander Sport, Chrysler 200, Kia Soul

The Ecology Center's fourth update of their consumer guide to toxic chemicals in cars lists the Honda Civic at the top (best pick) for fewest toxic chemicals, and the Mitsubishi Outlander Sport at the bottom of the list. Over 200 of the most popular 2011 and 2012 model vehicles were tested for chemicals that off-gas from parts such as the steering wheel, dashboard, armrests and seats. These chemicals contribute to new car smell and a variety of acute and long-term health concerns. Since the average American spends more than 1.5 hours in a car every day, toxic chemical exposure inside vehicles can be a major source of indoor air pollution.

According to Jeff Gearhart, Research Director at the Ecology Center, research shows that vehicle interiors contain a unique cocktail of hundreds of toxic chemicals that off-gas in small, confined spaces. Since these chemicals are not regulated, consumers have no way of knowing the dangers they face. The Ecology Center's testing is intended to expose these dangers and encourage manufacturers to use safer alternatives.

Chemicals of primary concern include: bromine (associated with Brominated Flame Retardants, or BFRs); chlorine (indicating the presence of polyvinyl chloride, or PVC and plasticizers); lead; and heavy metals. Such chemicals have been linked to a wide range of health problems such as allergies, birth defects, impaired learning, liver toxicity, and cancer. Automobiles are particularly harsh environments for plastics, as extreme air temperatures of 192 degrees F and dash temperatures up to 248�F can increase the concentration of Volatile Organic Compounds (VOC's) and break other chemicals down into more toxic substances.

The good news is overall vehicle ratings are improving. The best vehicles today have eliminated hazardous flame retardants and PVC. Today, 17 percent of new vehicles have PVC-free interiors and 60 percent are produced without BFRs.

Top ranking cars in recent years are: 1) Honda Civic 2) Toyota Prius and 3) Honda CR-Z. Worst ranking: 1) Mitsubishi Outlander Sport 2) Chrysler 200 SC and 3) Kia Soul. The Civic achieved its ranking by being free of bromine-based flame retardants in all interior components; utilizing PVC-free interior fabrics and interior trim; and having low levels of heavy metals and other metal allergens. The Mitsubishi Outlander contained bromine and antimony-based flame retardants in the seating and center console; chromium treated leather on several components; and over 400 ppm lead in seating materials.

Other Findings:

Most improved automakers in terms of average ratings for their vehicles are: VW (+42 percent) and Mitsubishi (+38 percent) and Ford (+30 percent). These represent improvement from the 2009/2010 models to the 2011/2012 models.

Two automakers had overall declining average scores from 2009/2010 to 2011/2012: Diamler AG (-29 percent) and Volvo (-13 percent).

On a fleet-wide basis PVC use is declining. Zero percent of pre-2006 vehicles had PVC-free interiors, as opposed to 17 percent (34) of the 2011/2012 vehicle models. Flexible PVC often contains hazardous plasticizers, or softeners, called phthalates, which off-gas during vehicle use and are deposited on dust particles and windshields, where they cause fogging. In recent years, automakers have begun replacing PVC with polyurethanes and polyolefins, which contain fewer harmful additives and are easier to recycle.

40 percent of vehicles tested in 2012 contained Brominated Flame Retardants (BFRs) in the vehicle interiors. BFRs refer to a wide range of chemicals added to materials to both inhibit their ignition and slow their rate of combustion. Alternatives exist which provide the degree of fire safety required under law without using organic compounds, as well as options in product redesign.



Update May 2024

New Study Finds Flame Retardant Chemical in New Car Interiors Continue to Pose Health Risks

Source: The Hill and Environmental Science & Technology


Millions of people are still being exposed to potentially toxic chemicals that are required by U.S. law to reduce fire hazards in new car interiors according to a study in Environmental Science and Technology. The foam padding inside car seats and other interior materials are required to contain flame retardants, or chemicals that make it harder for them to combust in a crash. These chemicals have been required since the 1970s, when the National Highway Traffic Safety Administration (NHTSA) passed a law requiring their use. However, experts disagree about their effectiveness. Patrick Morrison, of the International Association of Firefighters, says "these chemicals do little to prevent blazes — but instead simply make them “smokier and more toxic.”

Foam padding samples collected from all 101 cars tested by Duke University researchers contained the chemical tris (1-chloro-isopropyl) phosphate, or TCIPP. The U.S. National Toxicology Program is investigating TCIPP as a potential carcinogen. The vehicles included in the study ranged from model years 2015 to 2022, and included a broad range of both U.S. domestic and import makes.

Most of the cars that were sampled also had two other phosphate-based flame retardants that the state of California is investigating as potential carcinogens. These chemicals are tris (1,3-dichloro-2-propyl) phosphate (TDCIPP) and tris (2-ch loroethyl) phosphate (TCEP).

All of these chemicals are linked to reproductive and neurological problems, particularly because they do not stay in the fabrics they are woven into. Flame retardant chemicals off-gas or leach from the seat and interior fabrics into the air, especially during hot weather when car interiors can get as hot as 150 degrees F or higher.

Some experts are now saying the risks of these chemicals outweigh their flame retardant benefits.

Health researchers have found that the average U.S. child has lost up to 5 IQ points from exposure to flame retardants in cars and furniture. And adults with the highest levels of flame retardants in their blood face a risk of death by cancer that is four times greater than those with the lowest levels, according to the Journal of the American Medical Association.


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