Editing Letter box (section)

==Environmental conditions==
External or curbside letter boxes are not temperature-controlled, and this can sometimes be a concern for temperature-sensitive products such as [[pharmaceutical]]s, live plants or other organisms, or [[chocolate]] candies. Conditions can include high or low temperatures outside of the recommended storage conditions for certain products. For example, the [[USFDA]] found that the temperature in a steel mailbox painted black could reach {{convert|136|°F|°C|abbr=on}} in full sun while the ambient air temperature was {{convert|101|°F|°C|abbr=on}}.<ref>{{cite web | last = Black | first =J. C. |author2=Layoff, T | title = Summer of 1995 – Mailbox Temperature Excurions of St Louis | work = US FDA Division of Drug Analysis | url=http://www.layloff.net/articles/1995%20Mailbox%20Temp%20in%20STL.pdf | access-date = 12 July 2011}}</ref>