Before revision: Development By the 1960's researchers at the National Institute of Standards and Technology (NIST) had determined that the heat release from a fire was a major factor in the fire's risk to life and property.
After revision: Development By the 1960's researchers at the National Institute of Standards and Technology (NIST) had determined that the heat release from a fire directly related to the growth rate of a fire and was thus a major factor in the fire's risk to life and property.