As a 100% permanently and totally disabled USMC Veteran, I have hearing and pulmonary health problems from being close to (a few feet) and even far from (hundreds of yards to miles) generators. The constant noise and vibrations, and the chemicals, emissions, and fumes are quite well documented to cause mental and physical hazards, including loss of sleep, loss of hearing, airborne hazard health problems, and death due to the emissions.  For example, whether during my multiple deployments to Afghanistan, Iraq, or Japan, or in the U.S., the military would remind members to not sleep near generators due to death from the emissions. 
Thank you!