EV batteries are fully recyclable, and unlike the lead acid batteries in gas cars, are completely non-toxic and do not contain any heavy metals.
An EV battery contains around 10 kg of recyclable lithium versus the 10,000’s of kilograms of gasoline that is burnt by a gas car over its life.
Contrast the minimal impact of battery production with the numerous waste streams produced by gasoline powered cars, which include: all of the toxic by-products of mining, extracting processing and refining the fuels, the tonnes of emissions produced by each gasoline car each year, the billions of litres of polluted engine oil, transmission fluid and coolants resulting from servicing gas powered cars, the contamination from underground fuel tanks, pipeline leaks, train and truck accidents, the groundwater impacts of fracking, the pollution of the oceans from spills, ballast water and oil well blow outs, etc.  
Oil production is clearly orders of magnitude more toxic and harmful than batteries.