United States Nuclear Regulatory Commission - Protecting People and the Environment

EA-02-084 - Mallinckrodt, Inc.

May 10, 2002


Joel Timberlake
Vice PresidentImaging Operations
Mallinckrodt, Inc.
675 McDonnell Boulevard
P.O. Box 5840
St. Louis, MO 63134


Dear Mr. Timberlake:

This refers to the inspections conducted on October 23-24, 2001, and November 28-29, 2001, at the Mallinckrodt, Inc., Maryland Heights, Missouri, facility. The purpose of the inspections was to determine whether activities authorized by the license are being conducted safely and in accordance with NRC requirements. The inspections involved an examination of activities conducted under your license as they relate to radiation safety and to compliance with the Commission's rules and regulations and with the conditions of your license. At the conclusion of each inspection, the findings were discussed with you, Mr. Dale Simpson, and other Mallinckrodt representatives at an exit meeting, as well as in summary at a management meeting conducted on January 31, 2002. The meeting was open for public observation.

The enclosed report identifies areas that were examined by the inspectors. Within these areas, the inspection consisted of observations of work activities, interviews of personnel, reviews of selected procedures and records, and independent measurements.

By way of background, on June 22, 2000, the NRC issued a Confirmatory Order Modifying License to Mallinckrodt (Order). The Order was issued as a result of NRC concerns regarding 31 identified exposures in excess of regulatory limits in 10 CFR Part 20, and with the effectiveness of the radiation safety program. The Order confirmed a number of commitments and required that Mallinckrodt review past manufacturing processes to identify any additional examples of extremity exposures in excess of NRC regulatory limits.

The inspections were the fourth of a series of inspections that the NRC conducted in calendar year 2001. Two inspections were conducted each calendar quarter, followed by a management meeting between our respective organizations. The fourth quarter inspections included reviews of: (1) the additional reported extremity overexposures; (2) occupational doses in calendar year 2001-to-date; (3) air effluent monitoring and public dose; (4) observations of production, manufacturing, and laboratory activities; (5) dose calibrator quality control; (6) the status of commitments made to satisfy the June 22, 2000, Confirmatory Order; and (7) the corrective action program.

As required by the Order, Mallinckrodt, through the use of a contractor, had completed a review of past operations to identify other examples of significant extremity exposures due to contact handling of containers of radioactive material. On August 16, 2001, you received the contractor's report documenting the results of its review. The contractor identified 82 additional examples of extremity exposures in excess of 50 rem shallow-dose equivalent (SDE), including ten exposures in excess of 250 rems SDE. During our last inspection, we concluded that the methodology used by the contractor in determining the magnitude of the exposures was reasonable.

Based on our review of these events, we have concluded that your staff and contractors identified 117 extremity exposures in excess of 50 rems SDE that occurred in the period between 1995 and 2000. Sixteen of those exposures were in excess of 250 rems SDE, including one exposure associated with the direct handling of a molybdenum-99 generator column, that occurred on March 31, 2000. The other exposures were identified following the March 31 event and occurred due to routine manufacturing and laboratory processes, in which Mallinckrodt staff handled unshielded or partially shielded containers of radioactive material. Based on the results of our inspections since the March 31 event, we have concluded that all of those direct handling processes were corrected once you became aware of them, and that there have been no significant extremity exposures associated with those practices since June 2000.

On December 21, 2000, the NRC staff took significant enforcement action against Mallinckrodt, which included issuing a Severity Level I violation and a $125,000 civil penalty to address he compliance issues associated with the 31 overexposures identified at that time as well as the circumstances that resulted in those exposures. During our review of the additional 82 examples of extremity exposures in excess of 50 rem SDE, we determined that: (1) Mallinckrodt staff (or your contractor on your behalf) identified each of the additional overexposures as a result of your corrective actions implemented in response to the June 22, 2000 Order; (2) the root cause of the additional overexposures was the same as the root cause for the overexposures that formed the basis for our original enforcement action in December 2000 (i.e., failure to recognize the significant difference between the exposures to workers fingertips from contact handling and the doses recorded by extremity monitors worn by the workers); and (3) your immediate and long-term corrective actions were timely and comprehensive, in that the practices that contributed to all of the extremity overexposures had been identified by Mallinckrodt staff and corrected in June 2000.

The process breakdown which allowed the overexposures to occur and the failure to meet the regulations in place at the time, were considered significant, as evidenced by the previous enforcement action. Indeed, the overexposures were as much as eight times the limits in force at the time. We understand that you contacted most of the individuals whose extremities (finger tips) were overexposed and that there were no health effects identified as a result of the overexposure. The NRC recognizes that such doses to small areas of the skin result in insignificant overall health effects, such as reddening of the skin. Of note, the NRC recently amended its regulations in 10 CFR Part 20 to change the definition and method of calculating shallow-dose equivalents to the dose averaged over the 10 square centimeters of skin receiving the highest exposure, rather than 1 square centimeter (effective June 4, 2002).

The NRC has determined that had we been aware of all the extremity overexposures at the time that we took enforcement action in December 2000, the resulting action would not have been different. The Severity Level I violation in our December 21, 2000, enforcement action reflects the most significant categorization of violations available to the NRC, as defined in the NRC's Enforcement Policy, NUREG-1600, and we determined that the amount of the civil penalty imposed provided an adequate deterrent to both Mallinckrodt staff and other licensees from engaging in activities that could result in future similar violations. For these reasons, as well as the fact that you have taken timely and comprehensive corrective actions, and after consulting with the Commission, we have decided to exercise enforcement discretion and not issue a violation for the additional examples of extremity exposures in excess of 50 rem SDE, nor propose any additional enforcement action for these issues. As such, we consider these matters closed.

In accordance with 10 CFR 2.790 of the NRC's "Rules of Practice," a copy of this letter and its enclosure will be available electronically for public inspection in the NRC Public Document Room or from the Publicly Available Records (PARS) component of NRC's document system (ADAMS). ADAMS is accessible from the NRC Web site at the Public NRC Library.

We will gladly discuss any questions you have concerning this inspection.

/RA by J. Caldwell Acting for/
J. E. Dyer
Regional Administrator

Docket No. 03000001
License No. 24-04206-01

1. Inspection Report 030-00001/2001-005(DNMS)
2. Summary of January 31, 2002, Public Meeting

cc w/encls:
J. R. Powell, Interim Maryland Heights Site Manager
J. Schuh, Radiation Safety Officer

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