President Carter has shifted his position on price supports for sugar and defended his proposed regulations against cotton dust, which can cause "brown lung" in workers exposed to it in textile mills.

The president, in an interview Friday with the National Association of Farm Broadcasters, said he'd be willing to accept a federal support price for sugar of 15 cents a pund without any cost escalator - the figure recommended by the House Ways and Means Committee.

Previously, the Carter administration had insisted on a limit of 14.5 cents without an escalator for the five-year (1979-83) period contemplated by the sugar bill. The House Agriculture Committee favors 16 cents with an escalator, while a bill before the Senate Finance Committee calls for 17 cents with an escalator. The current price is about 14.5 to 14.6 cents, Agriculture Department spokesmen said.

"I think the Ways and Means bill . . . would be the maximum that I could accept on sugar prices," said Carter. "That is 15 cents with no annual built-in increase."

Carter also told the broadcasters that new regulations, lowering the amount of cotton dust allowed in the air of mills and other places where textiles are processed are "very reasonable." He added, "I doubt if there is any regulation that has been issued within the last 12 months that I put more time on personally."

He said cotton-dust control proposals by the previous Republican administration might have cost industry $7 billion to institute, while the ones issued by the Labor Department Sept. 4 had cut that cost substantially, perhaps to one-fourth. The Senate, nevertheless, voted last week to suspend the new regulations until May 1 in a rider to an appropriations bill.