Scientists for DuPont Co. will keep studying the effects of a chemical used to make Teflon because they can’t entirely rule out a connection to slightly elevated levels of kidney cancer, heart disease and diabetes among workers, the company said.

However, a health study released this week of about 6,000 current and former West Virginia employees shows death rates among workers no higher than at seven DuPont plants in other states, the population of West Virginia or the rest of the nation’s population, said Dr. Sol Sax, the company’s chief medical officer.