Editing Lethal dose (section)

==<span id="LC50"></span>Median lethal concentration==
For gases and aerosols, lethal concentration (given in mg/m<sup>3</sup> or ppm, parts per million) is the analogous concept, although this also depends on the duration of exposure, which has to be included in the definition. The term incipient lethal level is used to describe a LC<sub>50</sub> value that is independent of time.<ref>{{Cite book|title=Fish Physiology: Euryhaline Fishes, Volume 32|last=Schultz|first=Eric|publisher=Academic Press|year=2013|isbn=978-0-12-396951-4|pages=481–482}}</ref>

A comparable measurement is LCt<sub>50</sub>, which relates to lethal dosage from exposure, where C is concentration and t is time. It is often expressed in terms of mg-min/m<sup>3.</sup> LCt<span style="font-size:100%;"><sub>50</sub></span> is the dose that will cause incapacitation rather than death. These measures are commonly used to indicate the comparative efficacy of [[chemical warfare]] agents, and dosages are typically qualified by rates of breathing (e.g., resting = 10&nbsp;L/min) for inhalation, or degree of clothing for skin penetration.  The concept of Ct was first proposed by [[Fritz Haber]] and is sometimes referred to as [[Haber's law]], which assumes that exposure to 1 minute of 100&nbsp;mg/m<sup>3</sup> is equivalent to 10 minutes of 10&nbsp;mg/m<sup>3</sup> (1 × 100 = 100, as does 10 × 10 = 100).{{Citation needed|reason=A citation for what? 
There is a Wikipedia article about Haber''s law clearly linked to on the paragraph - please elaborate or remove this citation needed somebody, as I am not sure which to do.   Thank you.  date=April 2016|date=June 2017}}

Some chemicals, such as [[hydrogen cyanide]], are rapidly detoxified by the human body, and do not follow Haber's Law.  So, in these cases, the lethal concentration may be given simply as '''LC<sub>50</sub>''' and qualified by a duration of exposure (e.g., 10 minutes). The [[material safety data sheet]]s for toxic substances frequently use this form of the term even if the substance does follow Haber's Law.{{Citation needed|date=April 2016}}