This paper shows for a Korean case study how the naphtha storage fraction and CO2 emissions from naphtha use in the petrochemical industry can be estimated. We have used the Non-Energy use Emission Accounting Tables model to estimate CO2 emissions by subtracting the carbon stored in products from the total carbon input. We also value the country's naphtha storage fraction by calculating carbon storage in basic chemicals. The naphtha storage fraction and associated CO2 emissions from non-energy use depend on the production and trade structure of a country. Therefore, it is reasonable for Korea (with its large production and net exports of chemicals) to estimate a county-specific storage fraction. The naphtha storage fraction estimated using the Non-Energy use Emission Accounting Tables model was over 90% in Korea between 2011 and 2015. It is much higher than the Intergovernmental Panel on Climate Change default fraction of 75%. A revision of the naphtha storage fraction from 75 to 90% is proposed for Korea. The Intergovernmental Panel on Climate Change allows countries to apply their own values that more accurately represent their country's situation. The Korean government is advised to consider this finding in its national emission accounting.