Over the past 25 years, Probst has conducted numerous analyses of environmental programs, focusing mainly on improving the implementation of Superfund and other hazardous waste management programs. She was the lead author of the study, Superfund's Future: What Will it Cost?, requested by Congress, on the estimated cost of the Superfund program to the U.S. Environmental Protection Agency (EPA) from FY 2000 through FY 2009. Her 2004 study Success for Superfund, includes recommendations for specific information EPA should make readily available to the public on all Superfund sites, in a site "report card." In February 2004, Probst organized a workshop at RFF on estimating the economic impacts from the reuse of contaminated properties. Probst's most recent work is a short policy paper Combating Global Warming: One Car at a Time, where she proposes that EPA require a C02 emissions label for all new cars and light trucks.