Black workers end up with private retirement pensions far less often than whites, according to a government study published yesterday. The study, reported in the Social Security Bulletin, is based on the histories of thousands of workers who were between age 58 and 63 in 1969 and had reached retirement age by 1974.

The study shows that black workers in this group were far less likely to have worked in pension-covered employment during the longest job they ever held. If they did, they were far less likely to become vested and end up receiving benefits.

The figures reveal that only 20 percent of the blacks worked in covered jobs, compared with 43 percent of the whites.

And of those workers in covered jobs, only 52 percent of the blacks ended up with pensions by 1974, compared with 77 percent of the Whites.

The author of the study, Gayle B. Thompson, said one major reason for these differences is the kinds of jobs blacks hold.

They are less likely to hold manufacturing, professional and technical jobs - the kind where pension systems most commonly are in existence - and more likely to hold nonprofessional service and labor jobs where fewer firms have private pension systems.

Moreover, because of discrimination, lack of training and the like, blacks tended to end up with more service breaks and fewer years of service, so they were "less likely to have the long tenure and recent employment necessary for the receipt of pension benefits upon retirement."

The study involved workers who retired before the 1974 Employe Retirement Income Security Act, which improved worker protections in private pension systems. So the author notes that some of the guarantees in that law may "result in expanded coverage and in higher receipt rates for black workers with short tenure and discontinuous work histories."

But Thompson said the black worker pension coverage and vesting won't greatly expand until they are in the kinds of jobs where private pensions are prevalent.