1005. The explosive range of benzene is 1.4% to 8% by volume in air. If you sample an empty tank that had contained benzene and obtained a reading of 50% L.E.L. on a combustible gas indicator, then the __________.

A combustible gas indicator reading of 50% LEL indicates a benzene vapor concentration of 0.7%, which is below the lower explosive limit (1.4%), rendering the mixture too lean to burn and outside the flammable range; therefore, all related statements are accurate.