Wal-Mart has pleaded guilty to criminal charges on hazardous waste practices. The company has agreed to pay $81 million, the Environmental Protection Agency said.

There were previous actions from California and Missouri and combined the company will pay $110 million to resolve the cases.

The cases were filed in Los Angeles and San Francisco and the company pleaded guilty to six counts of violating the Clean Water Act because they handled and disposed of hazardous materials innapropriately in its retail stores across the US, reported the AP.

The company also pleaded guilty in Kansas City, Mo., for not properly handling pesticides returned by customers at stores across the country.

'This case is as big as Wal-Mart is," says Assistant U.S. Attorney Joe Johns, chief of the Justice Department's environmental crimes section in Los Angeles to the AP. "This conduct is alleged to have taken place at every single Walmart in the country."

The practices continued until January 2006. Some of the hazardous waste was put in trash bins, or poured in the local sewer system or was improperly transported.

"By improperly handling hazardous waste, pesticides and other materials in violation of federal laws, Wal-Mart put the public and the environment at risk and gained an unfair economic advantage over other companies," said Ignacia Moreno, assistant attorney general for the Justice Department's Environment and Natural Resources Division to the AP.

In 2010 Wal-Mart paid  $27.6 million to settle a suit that said it improperly handled and dumped hazardous waste at various stores. The allegations claim that the chain dumped the waste at stores across California. The settlement ended a five year investigation, reports the Associated Press.

San Diego County District Attorney Bonnie Dumanis stated that the company's stores including 236 stores and distribution centers in California as well as Sam's Club warehouse stores, violated environmental laws and regulation.

The company will pay the $20 million to prosecuting and investigating agencies and then more than $1.6 million in investigative costs and $3 million for environmental projects. The company will also invest $3 million to ensure that the stores will comply to the rules.

"Wal-Mart was accused of improperly disposing of pesticide, fertilizer, paint, aerosols and other chemicals. In one case, Dumanis said a Solano County boy was found playing in a mound of fertilizer near a Walmart garden section. The yellow-tinted powder contained ammonium sulfate, a chemical compound that causes irritation to people's skin, eyes and respiratory tract," reported the AP.