Holliston is holding a household hazardous-waste collection July 20 from 9 a.m. to noon at the Adams Middle School. The town has hired environmental contractor Clean Harbors to handle the disposal of most household waste material that cannot be included in routine trash collections. According to a posting on the municipal website, all materials should be labeled and in their original container, if possible, as a safety measure. Unmarked items will be tested to determine their eligibility for disposal. Acceptable materials include aerosol cans, antifreeze, batteries, brake fluid, caulking, cesspool cleaners, fiberglass, insect sprays, oven cleaners, oil-based paint products, and rodent killers. Safe Harbors reserves the right to refuse any waste deemed unsafe to handle, including large quantities of unknown waste, medical waste, radioactive waste, explosives or gun powder, flares or ammunition, and pressurized fire extinguishers. Latex paint will not be accepted because it is not considered hazardous waste and can be thrown out with regular trash once it is completely dried out. For more details, visit www.townofholliston.us Full story for BostonGlobe.com subscribers.