Developers will be allowed to leave substantially more arsenic and lead in the soil deep below contaminated construction sites under new state rules, leading environmental advocates to accuse the Patrick administration of rolling back key public health protections.
The regulations, slated to take effect this spring, would double the amount of lead and increase by 150 percent the amount of arsenic allowed to remain in dirt 15 feet or more below the surface. Pollutants at those depths rarely present a public safety hazard unless they are dug up during construction, and the state Department of Environmental Protection says the changes are supported by scientific studies.
Critics worry the rules will spur developers to build on contaminated land, known as brownfields, potentially creating plumes of toxic dust and sludge that can get into waterways and the air. Full story for BostonGlobe.com subscribers.