21 C.F.R. § 230.205
The applicant shall submit a field alert report containing all information described in paragraphs (a) and (b) of this section about distributed designated medical gases and articles to the FDA district office that is responsible for the facility involved as soon as possible but no later than 45 calendar days from the date the applicant, or its agent or contractor, obtained information suggesting that a reportable incident has occurred. If the information suggests that the reportable incident may require a rapid response to address a public health risk, the applicant must as soon as possible, but no later than 3 working days from obtaining the information, submit a field alert report. The information may be provided by telephone or other rapid communication means, with prompt written followup. The report and its mailing cover should be plainly marked: "Designated Medical Gas-Field Alert Report."
21 C.F.R. §230.205