The Environmental Protection Agency has one small obstacle between it and the massive personnel cuts it is planning over the next two years: its federal employe union local.

EPA expects to vaporize the jobs of "about 650 people" during fiscal 1982, which ends next Sept. 30, according to a top personnel official who asked not to be identified. An additional 2,000 or so positions are expected to be scrapped in 1983 under a further 18 percent proposed budget cut.

However, not one job may be eliminated until EPA reaches agreement over "reduction-in-force" (RIF) procedures with the American Federation of Government Employes. Negotiations began last Thursday and nobody expects them to end soon.

"I've been trying to get 'em to negotiate a master contract with us ever since July of 1980," six months after the EPA National AFGE Council was formed from 10 regional and Washington EPA office units, said council president Harold Dodson. "It would have taken six months and we wouldn't be in this position."

The EPA personnel official said negotiations didn't start earlier because Dodson never submitted concrete proposals. But EPA opened matters in August with its own plan, which Dodson summarily rejected as too sketchy. "Well, that's the whole point of negotiating," the official said.

The official said about 150 RIF notices have been sent to EPA employes in Boston; Cincinnati; Sandusky, Ohio; Kansas City, and Research Triangle Park, N.C., under agreements reached with local AFGE units. But Dodson said only the council has authority over those RIFs.

Dodson has defined the main negotiation issue as the so-called "RIF pools," the competitive areas within which workers whose jobs are eliminated may try to get other jobs.