The House Science, Space, and Technology Committee is probing the Environmental Protection Agency’s use of humans as guinea pigs to test high levels of air pollution.

Investigations and Oversight Subcommittee Chairman Paul Broun (R-Ga.) asked the EPA’s inspector general, Albert Elkins, to review the human research studies conducted since 2004.

In these studies, test subjects — many of them unhealthy and elderly adults — were exposed to high levels of air pollutants such as diesel exhaust and fine particulate matter more than 20 times higher than the EPA standard.

“I am concerned about the individuals EPA asked to participate in these studies, which included unhealthy and elderly adults who, in some cases, were explicitly selected to participate because they suffered from moderate asthma and metabolic syndrome,” Broun wrote. “My concerns appear to be justified by the experiences of two study subjects who participated in EPA experiments between January 5, 2010 and June 9, 2011 when 41 human study subjects were exposed to PM2.5 levels ranging from 41.54 micrograms per cubic meter to 750.83 micrograms per cubic meter for periods of up to 2 hours.”

In October 2010, a 58-year-old test subject with a history of heart and other health problems had to be taken to the hospital because of atrial fibrillation.

Broun gave the inspector general an April 2013 deadline to explain what rules are in place, if any, regarding what human test cases can be exposed to and how the agency protects test subjects from premature death.

In a congressional hearing last year, EPA Administrator Lisa Jackson compared the lethality of particulate matter to cancer.

“Particulate matter causes premature death.  It doesn’t make you sick.  It’s directly causal to dying sooner than you should,” she said. “If we could reduce particulate matter to healthy levels it would have the same impact as finding a cure for cancer in our country.”