The Iowan who led the charge to assure broader civil rights for people with disabilities more than two decades ago says his work in that effort is far from over. Iowa Senator Tom Harkin is marking this month’s 21st anniversary of the landmark legislation he authored, known as the Americans with Disabilities Act, or A.D.A.

Harkin says, “Despite the progress, the harsh reality is that people just really still experience discrimination and one of the toughest challenges we still need to tackle is the persistently low employment rates among Americans with disabilities.” Harkin is chairing a hearing today  of the Health, Education, Labor and Pensions Committee which will focus on expanding employment opportunities for people with disabilities.

“According to the Bureau of Labor Statistics, less than a third of working-aged people with disabilities are participating in the labor force,” Harkin says. “Put another way, two-thirds of them are unemployed.” Harkin, a Democrat, says the A.D.A. has been a great benefit to millions of people over the past 21 years, but some issues clearly still need tweaking.

“It’s worked in things like accessibility, transportation, building standards,” Harkin says. “It’s worked in all those areas. One place where it’s been so frustrating is in the employment sector.”

The labor bureau report finds the nation’s workforce of people with disabilities is at more than five-million — covering both people who are working and those looking for work. He wants to see that figure at six-million by 2015.