Nine-volt battery batteries were formerly made in this size. They had higher capacity than the then-standard carbon-zinc types, a nominal voltage of 8.4 volts, and very stable voltage. Once used in photographic and measuring instruments or long-life applications, they are no longer manufactured as mercury is highly toxic and accumulates in the ecosystem, posing a risk to humans and wildlife. Most battery voltage testers and chargers that can also test nine-volt need another snap clip to hold the battery, while cylindrical batteries often share a holder that may be adjustable in size. Because of the proximity of the positive and negative terminals
Health and safety hazards of nanomaterials workers, disposal services, and others. This may require toxicological or other testing, and all data or information provided must be vetted by properly controlled testing The ISO/TR 13329 standard provides guidance specifically on the preparation of safety data sheets for nanomaterials. The National Institute for Occupational Safety and Health does not issue regulations, but conducts research and makes recommendations to prevent worker injury and illness. State and local governments may have additional regulations. The Environmental Protection Agency (EPA) regulates nanomaterials under the Toxic Substances Control Act, and has permitted limited manufacture of new chemical nanomaterials through the use of consent