P-D-680 (A-A-59601) is a petroleum-based solvent, which contains hazardous air pollutants (HAPs) and volatile organic compounds (VOCs), and causes health and environmental concerns.  Its successor, MIL-PRF-680, is also a petroleum-based solvent which contains the same amount of VOC as P-D-680 but does not contain HAPs. Solvent emissions are regulated regionally and locally, with the Air Pollution Control Districts in California implementing the most stringent requirements.  The San Joaquin Valley Air Pollution Control District (SJVAPCD) has recently imposed restrictions limiting the use of solvents with VOC content to no greater than 25 grams per liter for immersion cleaning processes unless the solvent is used in an airtight cleaning system.
A need exists for a specification to classify and qualify products that are low-VOC and HAP-free to meet these new environmental regulations. This specification covers non-aqueous cleaning solvents that are free of hazardous air pollutants and contain a low amount (no more than 25 grams per liter) of volatile organic compounds for cleaning air, sea, and ground vehicle components and support equipment.  The requirements for the new specification include the following properties: non-ozone depleting substances (non-ODS), HAP-free, low-VOC (25 g/L), effective cleaning efficiency, non-toxic, compatible with metals and non-metal substrates, and safe to use.  The new specification will not replace MIL-PRF-680 totally but will target specific cleaning applications. The new specification consists of two types; Type I is intended for cleaning light soils such as oils and hydraulic fluids, and Type II is intended for cleaning heavy soils such as greases and carbon residues.