June 22, 2015  |  Philly.com

Atomic bombs, leaded gasoline, Teflon: DuPont Co. built materials that powered the products defining American industrial and military might in the 20th century.

Jobs have been scaled way back at old DuPont sites along the Delaware, Ohio, and other great rivers. But the plants remain home to caustic and cancer-causing byproducts, held back by pumps, pipes, and barriers, not to mention litigation and negotiations with local governments, community groups, and regulators.

Who’s going to manage these long-term threats, now that DuPont is spinning off old chemical units into a smaller new company, Chemours, on July 1?

“DuPont and Chemours remain committed to continuing to fulfill all of their environmental and legal obligations in accordance with existing local, state, and federal regulatory guidelines,” company spokesman Daniel A. Turner told me.

In fact, Chemours is taking over many cleanup responsibilities from its parent company for an “indefinite” period, according to documents it has recently filed with the Securities and Exchange Commission. The “ultimate costs are difficult to accurately predict,” Chemours added. Its long-term obligations are “uncapped.”

Chemours accounts for $7 billion of DuPont’s $35 billion in yearly sales.

The spinoff may end up owing billions more than it can pay, without DuPont’s deeper pockets, Maggie Flanigan, spokeswoman for Parkersburg, W.Va.-based Keep Your Promises DuPont, a community activist group, told me…