Warning Letter of the Week: dead legs and rusty pipes edition

From a letter from the Center for Drug Evaluation and Research to the Chairman of the Board of Guangzhou Tinci Materials Technology Co., Ltd.:

Your [redacted] and distribution systems appear to have multiple dead-legs, which can foster the development of biofilms. The piping and installation diagrams for your [redacted] system in your response lack adequate information regarding the slope of the piping. 

Moreover, your [redacted] system lacks proper maintenance. For example, there were visible corrosion on pipes, brackets, fittings, valves, and tanks in the utilities area, which is covered but not completely enclosed from outside elements. During the inspection, you stated that some poorly maintained equipment and piping in the [redacted] utility area is not currently in use. However, during the inspection it appeared that the poorly maintained equipment and piping was still connected to the [redacted] system you use to make components of drugs.

I genuinely didn't know the FDA disapproves of dead legs, although biofilms are a perfectly good reason why.