Skip Navigation LinksSkip Navigation Links
Centers for Disease Control and Prevention
Safer Healthier People
Blue White
Blue White
bottom curve
CDC Home Search Health Topics A-Z spacer spacer
Blue curve MMWR spacer

Investigating Problems with Respirators

From July 1, 1983, through June 30, 1984, the National Institute for Occupational Safety and Health (NIOSH) received 35 reports of problems with respirators* (Table 4). Investigations of each report revealed that 21 (60%) of the problems involved self-contained breathing apparatus; nine of these were classified as causing or likely to cause immediate death or illness of or injury to the user. A report of one investigation follows.

On July 15, 1983, a manufacturer of compressed-gas cylinders notified NIOSH of reported cracks in some of its cylinders. These cylinders were used in various breathing apparatus that had been approved by NIOSH and the Mine Safety and Health Administration (MSHA), U.S. Department of Labor, in their joint program for respirator approval. Company officials indicated that one of the cracked cylinders had ruptured; at least one other cracked cylinder was later reported to have ruptured. Since all defective cylinders were discovered in storage or during maintenance, no adverse effects occurred to workers; however, the defects were classified as potentially life-threatening.

Several respirators, previously approved by NIOSH, incorporated the potentially defective cylinders produced by the company. All manufacturers of these respirators were contacted, and although each stocked this company's cylinders, only two had sold units containing cylinders with serial numbers specified by the company. Approximately 7,000 cylinders were potentially defective, and about 2,000 of these were estimated to be in the hands of users. On July 21, 1983, NIOSH issued a Warning to Users, describing the problem, identifying the serial numbers, and recommending that the potentially defective cylinders be emptied and not used. The U.S. Department of Transportation (DOT), which regulates the interstate shipment of compressed-gas cylinders, then issued a notice to recall the cylinders. After further ruptures occurred, DOT, in February 1984, reduced the allowable pressure for these cylinders from 4,500 to 4,000 pounds per square inch. NIOSH issued a Notice to Users on February 29, 1984, advising owners of more than 75,000 cylinders manufactured by this company of this requirement for reduced pressure and of the reduced service time that results from the required reduction in pressure. No further ruptures have occurred in cylinders with reduced pressure, and as cracked cylinders are found during the ongoing schedule of physical examinations, they are removed from service. Reported by Certification Br, Div of Safety Research, National Institute for Occupational Safety and Health, CDC.

Editorial Note

Editorial Note: The joint NIOSH/MSHA program for approving respirators is mandated by the Mine Safety and Health Amendments Act of 1977. It is conducted in accordance with requirements published in the Code of Federal Regulations, Title 30, Part 11. The Occupational Safety and Health Administration and several other federal regulatory agencies require the use of NIOSH/MSHA-approved respirators wherever such devices are needed to protect workers.

NIOSH receives reports of problems identified in approved respirators from respirator users and from investigations carried out by manufacturers. Problems include deficiencies in the design and performance of respirators and difficulties with their use. NIOSH classifies reported problems according to their potential for causing adverse health effects. Problems classified "A" have resulted in or are likely to result in immediate death or illness of or injury to the user. Those classified "B" may result in future illness of the user. Those classified "C" will probably lead to a worker either rejecting or refusing to wear a respirator. Problems classified "D" have no apparent immediate or future effect on the health and safety of the user. NIOSH notifies the respirator manufacturer of the reported problems and requests an investigation and corrective action, if needed. This information is also used in research to improve the design and performance of respirators. NIOSH may request that defective respirators be recalled, retrofitted, or replaced. Sale of the respirator as a NIOSH/MSHA-approved apparatus may also be stopped. When necessary, users of respirators are alerted to deficiencies or difficulties that could affect their health and safety. If the manufacturer cannot identify and notify purchasers of the defective respirators, NIOSH issues a warning to more than 9,000 users of respirators and other interested persons.

Users of NIOSH/MSHA-approved respirators who find defects in or notice inadequate performance of approved respirators are asked to report these findings to: Respirator Problem Coordinator, Certification Branch, Division of Safety Research, NIOSH, 944 Chestnut Ridge Road, Morgantown, West Virginia 26505; phone: (304) 291-4595 or FTS 923-4595. *Any device designed to provide the wearer with respiratory protection against inhalation of a hazardous atmosphere.

Disclaimer   All MMWR HTML documents published before January 1993 are electronic conversions from ASCII text into HTML. This conversion may have resulted in character translation or format errors in the HTML version. Users should not rely on this HTML document, but are referred to the original MMWR paper copy for the official text, figures, and tables. An original paper copy of this issue can be obtained from the Superintendent of Documents, U.S. Government Printing Office (GPO), Washington, DC 20402-9371; telephone: (202) 512-1800. Contact GPO for current prices.

**Questions or messages regarding errors in formatting should be addressed to

Page converted: 08/05/98


Safer, Healthier People

Morbidity and Mortality Weekly Report
Centers for Disease Control and Prevention
1600 Clifton Rd, MailStop E-90, Atlanta, GA 30333, U.S.A


Department of Health
and Human Services

This page last reviewed 5/2/01