The study, conducted by non-profit group the Ecology Center and published on its HealthyStuff website, found more than 275 different chemicals in vehicle interiors, including some associated with cancer, birth defects, impaired learning and liver toxicity. Long-term exposure to small amounts of these pollutants can negatively impact health, and children are at greater risk of developing health problems from exposure.
Despite this, there is no mandatory testing or regulation of chemicals used in vehicles.
The study tested 204 vehicles from the 2011/2012 model years, adding to its database of more than 900 vehicles that it started in 2006.
The best car in the latest round of testing was the 2012 Honda Civic. The study explains the new Civic is free of bromine-based flame retardants, uses PVC-free fabrics and trim materials, and has low levels of heavy metals and other metal allergens.
Honda continues to be the top-rated manufacturer for healthy interiors based on the data collected since the Ecology Center started its research, although Hyundai-Kia has been the best performer for the past two years.
The Toyota Prius and Honda CR-Z also rated highly in the 2012 study, while Volkswagen, Mitsubishi and Ford were among the best improvers for the year.
At the other end of the scale, the Mitsubishi Outlander Sport (ASX in Australia), Chrysler 200 and Kia Soul were all rated ‘high’ for interior chemical toxicity. The study explains the Mitsubishi contains bromine- and antimony-based flame retardants in the seats and centre console, chromium-treated leather, and more than 400ppm lead in seat materials.
The study shows the majority of manufacturers are cleaning up their interiors. Less than one per cent of pre-2006 vehicles had PVC-free interiors. This year, the number has risen to 17 per cent. Asian manufacturers are leading the shift away from PVC interior components, followed by Europe, with the US dragging its feet.
Note: US-spec vehicles tested. Interior materials may differ for vehicles sold in Australia.