US retail titan Walmart has been accused of illegally dumping more than 1 million toxic items into landfills every year.

Walmart US flag

The world’s largest bricks-and-mortar retailer is facing a lawsuit from the state of California over allegedly dumping discarded or returned products including aerosol cans, electronic waste, batteries, toxic cleaning supplies and other hazardous waste.

California attorney general Rob Bonta, who filed the lawsuit on Monday, said: “When a big-box store disposes of unwanted goods, just like the rest of us, they need to do so properly. Unfortunately, Walmart, the largest company in the world by revenue, has failed to do that on a grand scale here in California.”

The attorney general’s office settled a similar lawsuit back in 2010. On that occasion, Walmart paid out $25m (£18.8m) and pledged to stop dumping such products into California landfills that were not supposed to contain them.   

Walmart, which operates more than 300 stores across the state, also shelled out $1.25m (£944,000) to Missouri in 2012 to settle a similar claim.

Walmart spokesman Randy Hargrove told The Guardian: “The state is demanding a level of compliance regarding waste disposal from our stores of common household products and other items that goes beyond what is required by law.” 

Hargrove insisted the lawsuit was “unjustified”, adding that from almost 4,000 audits overseen by the attorney general’s office since 2010, Walmart’s trash compactors contained “at most 0.4% of items of potential concern”. 

But Bonta said Walmart’s own inspections showed it illegally disposed of almost 80 tons of toxic waste every year – the equivalent of more than 1 million items. 

“It’s not rocket science,” he said. “You can’t be sending these hazardous waste products into the general stream of sanitation. It’s dangerous, it’s unhealthy.”