Because he was always in such close proximity to Hillary, it was something he was carrying for his own benefit - it was Febreze.
“Secret Service Special Agent Todd Madison, a.k.a. “Hillary’s handler,” died at a Wisconsin hospital on December 8, 2017, at age 49 after serving 20 years with the agency protecting some of the most high-profile countrymen and women including the Clintons during their tenure at the White House.”
~ reported by various sources.