Startling research reveals 60 per cent of child car seats contain dangerous chemicals that can lead to learning difficulties, liver damage and cancer.US-based consumer website HealthyStuff.org tested more than 150 child car seats for bromine (used in flame retardants), chlorine (in PVC), lead, other heavy metals and allergens, and discovered three in five new products currently on sale in the US contain at least one of these substances.Heat and UV-ray exposure is known to accelerate the breakdown of these chemicals and potentially increase their toxicity.Babies are the most vulnerable demographic when it comes to exposure to chemicals, as their bodily systems are still developing.Research director at HealthyStuff’s Ecology Center, Jeff Gearhart, said the results of the investigation provided parents with more information about the long-term safety of the child seats on the market.“Car seats save lives. It's absolutely essential that parents put their children in them while driving,” Mr Gearhart said."However, our research shows that some car seats contain more harmful chemicals than others.”The report highlights the best and worst seats in terms of chemical toxicity:2011 Most Toxic car seats:Infant seat – Graco SnugRide 35 in Edgemont Red/Black and SnugRide 30 in AspreyConvertible seat – Britax Marathon in Platinum and Marathon 70 in Jet SetBooster seat – Recaro Pro Booster in Blue Opal and ProSPORT Toddler in Mist2011 Least Toxic car seats:Infant seat – Chicco KeyFit 30 in Limonata, Graco Snugride 35 in Laguna Bay and Combi Shuttle 33 in Cranberry NocheConvertible Carseat – Graco Comfort Sport in Caleo, Graco MyRide 65 in Chandler and Streamer, Safety 1st OnSide Air in Clearwater and Graco Nautilus Elite 3-in-1 in GabeBooster Seat: Graco Turbo Booster in Anders(Note: The investigation tested car seats sold in the US. Specifications may differ in Australia.)Overall, the toxicity levels of child car seats are improving rapidly. Since the Ecology Center’s first study in 2008, average ratings have improved by 64 per cent.