Volatile organic compounds (VOCs), solvents that add to smog, or solvents with high global warming potential (GWP) have been a focus of a number of regulators. Some state (e.g. CARB, the California Air Review Board), municipal, and even industry-specific regulations restrict the use of high VOC or high GWP materials.
To complicate things, VOC is defined and measured differently by various agencies. A degreaser might be considered low-VOC according to the standard EPA (Environmental Protection Agency) definition but may be high according to CARB. If low-VOC is the goal, Techspray sells cleaners with minimal VOC under the Precision-V brand.