| Agent Name | X-RADIATION |
| CAS # | |
| RTECS # | |
| Agent Code | P0450 |
| Code | Occupation Description (1980) | No Control |
Resp Prot |
Other PPE |
Vent |
Other Control |
Exposures |
| 019 | MANAGERS AND ADMINISTRATORS, N.E.C. | 0.0% |
0.0% |
100.0% |
0.0% |
0.0% |
806 |
| 086 | VETERINARIANS | 0.0% |
0.0% |
74.5% |
0.0% |
25.5% |
18,387 |
| 206 | RADIOLOGIC TECHNICIANS | 0.0% |
0.0% |
50.0% |
0.0% |
50.0% |
1,532 |
| 208 | HEALTH TECHNOLOGISTS AND TECHNICIANS, N.E.C. | 0.0% |
0.0% |
77.5% |
0.0% |
22.5% |
2,491 |
| 223 | BIOLOGICAL TECHNICIANS | 0.0% |
0.0% |
100.0% |
0.0% |
0.0% |
3,794 |
| 453 | JANITORS AND CLEANERS | 0.0% |
0.0% |
100.0% |
0.0% |
0.0% |
806 |
| 487 | ANIMAL CARETAKERS, EXCEPT FARM | 0.0% |
0.0% |
72.7% |
0.0% |
27.3% |
11,620 |
| SUBTOTAL | 0.0% |
0.0% |
76.7% |
0.0% |
23.2% |
39,436 | |
| Code | Occupation Description (1980) | No Control |
Resp Prot |
Other PPE |
Vent |
Other Control |
Exposures |
| 453 | JANITORS AND CLEANERS | 100.0% |
0.0% |
0.0% |
0.0% |
0.0% |
292 |
| 768 | CRUSHING AND GRINDING MACHINE OPERATORS | 100.0% |
0.0% |
0.0% |
0.0% |
0.0% |
44 |
| 888 | HAND PACKERS AND PACKAGERS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
785 |
| SUBTOTAL | 29.9% |
0.0% |
0.0% |
0.0% |
70.0% |
1,121 | |
| Code | Occupation Description (1980) | No Control |
Resp Prot |
Other PPE |
Vent |
Other Control |
Exposures |
| 453 | JANITORS AND CLEANERS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
83 |
| 757 | SEPARATING, FILTERING, AND CLARIFYING MACHINE OPERATORS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
12 |
| 769 | SLICING AND CUTTING MACHINE OPERATORS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
12 |
| 777 | MISCELLANEOUS MACHINE OPERATORS, N.E.C. | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
822 |
| 889 | LABORERS, EXCEPT CONSTRUCTION | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
119 |
| SUBTOTAL | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
1,048 | |
| Code | Occupation Description (1980) | No Control |
Resp Prot |
Other PPE |
Vent |
Other Control |
Exposures |
| 095 | REGISTERED NURSES | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
23 |
| 216 | ENGINEERING TECHNICIANS, N.E.C. | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
7 |
| 224 | CHEMICAL TECHNICIANS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
604 |
| 225 | SCIENCE TECHNICIANS, N.E.C. | 50.0% |
0.0% |
0.0% |
0.0% |
50.0% |
548 |
| 235 | TECHNICIANS, N.E.C. | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
512 |
| 453 | JANITORS AND CLEANERS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
329 |
| 889 | LABORERS, EXCEPT CONSTRUCTION | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
165 |
| SUBTOTAL | 12.5% |
0.0% |
0.0% |
0.0% |
87.4% |
2,188 | |
| Code | Occupation Description (1980) | No Control |
Resp Prot |
Other PPE |
Vent |
Other Control |
Exposures |
| 019 | MANAGERS AND ADMINISTRATORS, N.E.C. | 0.0% |
0.0% |
46.0% |
0.0% |
54.0% |
87 |
| 073 | CHEMISTS, EXCEPT BIOCHEMISTS | 61.5% |
0.0% |
11.0% |
0.0% |
27.5% |
127 |
| 216 | ENGINEERING TECHNICIANS, N.E.C. | 0.0% |
0.0% |
61.4% |
0.0% |
38.6% |
43 |
| 224 | CHEMICAL TECHNICIANS | 81.7% |
0.0% |
0.9% |
0.0% |
17.5% |
800 |
| SUBTOTAL | 69.2% |
0.0% |
8.2% |
0.0% |
22.5% |
1,057 | |
| Code | Occupation Description (1980) | No Control |
Resp Prot |
Other PPE |
Vent |
Other Control |
Exposures |
| 216 | ENGINEERING TECHNICIANS, N.E.C. | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
230 |
| 335 | FILE CLERKS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
231 |
| SUBTOTAL | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
461 | |
| Code | Occupation Description (1980) | No Control |
Resp Prot |
Other PPE |
Vent |
Other Control |
Exposures |
| 059 | ENGINEERS, N.E.C. | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
24 |
| 073 | CHEMISTS, EXCEPT BIOCHEMISTS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
12 |
| 889 | LABORERS, EXCEPT CONSTRUCTION | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
366 |
| SUBTOTAL | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
402 | |
| Code | Occupation Description (1980) | No Control |
Resp Prot |
Other PPE |
Vent |
Other Control |
Exposures |
| 073 | CHEMISTS, EXCEPT BIOCHEMISTS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
103 |
| 216 | ENGINEERING TECHNICIANS, N.E.C. | 2.4% |
0.0% |
0.0% |
0.0% |
97.6% |
1,198 |
| 225 | SCIENCE TECHNICIANS, N.E.C. | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
273 |
| 633 | SUPERVISORS, PRODUCTION OCCUPATIONS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
22 |
| 707 | ROLLING MACHINE OPERATORS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
1,320 |
| 723 | METAL PLATING MACHINE OPERATORS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
119 |
| 724 | HEAT TREATING EQUIPMENT OPERATORS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
152 |
| 749 | MISCELLANEOUS TEXTILE MACHINE OPERATORS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
288 |
| 777 | MISCELLANEOUS MACHINE OPERATORS, N.E.C. | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
761 |
| 779 | MACHINE OPERATORS, NOT SPECIFIED | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
416 |
| 783 | WELDERS AND CUTTERS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
247 |
| 889 | LABORERS, EXCEPT CONSTRUCTION | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
144 |
| SUBTOTAL | 0.5% |
0.0% |
0.0% |
0.0% |
99.4% |
5,043 | |
| Code | Occupation Description (1980) | No Control |
Resp Prot |
Other PPE |
Vent |
Other Control |
Exposures |
| 095 | REGISTERED NURSES | 43.9% |
0.0% |
0.0% |
0.0% |
56.1% |
63 |
| 585 | PLUMBERS, PIPEFITTERS, AND STEAMFITTERS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
135 |
| 797 | PRODUCTION TESTERS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
9 |
| SUBTOTAL | 13.3% |
0.0% |
0.0% |
0.0% |
86.6% |
207 | |
| Code | Occupation Description (1980) | No Control |
Resp Prot |
Other PPE |
Vent |
Other Control |
Exposures |
| 045 | METALLURGICAL AND MATERIALS ENGINEERS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
25 |
| 203 | CLINICAL LABORATORY TECHNOLOGISTS AND TECHNICIANS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
87 |
| 215 | MECHANICAL ENGINEERING TECHNICIANS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
58 |
| 216 | ENGINEERING TECHNICIANS, N.E.C. | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
7 |
| 225 | SCIENCE TECHNICIANS, N.E.C. | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
44 |
| 453 | JANITORS AND CLEANERS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
411 |
| 759 | PAINTING AND PAINT SPRAYING MACHINE OPERATORS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
51 |
| SUBTOTAL | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
683 | |
| Code | Occupation Description (1980) | No Control |
Resp Prot |
Other PPE |
Vent |
Other Control |
Exposures |
| 059 | ENGINEERS, N.E.C. | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
148 |
| 073 | CHEMISTS, EXCEPT BIOCHEMISTS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
24 |
| 095 | REGISTERED NURSES | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
7 |
| 213 | ELECTRICAL AND ELECTRONIC TECHNICIANS | 27.2% |
0.0% |
6.7% |
0.0% |
66.1% |
1,100 |
| 216 | ENGINEERING TECHNICIANS, N.E.C. | 0.0% |
0.0% |
0.7% |
0.0% |
99.3% |
1,578 |
| 224 | CHEMICAL TECHNICIANS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
6 |
| 225 | SCIENCE TECHNICIANS, N.E.C. | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
147 |
| 235 | TECHNICIANS, N.E.C. | 100.0% |
0.0% |
0.0% |
0.0% |
0.0% |
688 |
| 308 | COMPUTER OPERATORS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
66 |
| 447 | NURSING AIDES, ORDERLIES, AND ATTENDANTS | 0.0% |
0.0% |
66.7% |
0.0% |
33.3% |
88 |
| 453 | JANITORS AND CLEANERS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
365 |
| 549 | NOT SPECIFIED MECHANICS AND REPAIRERS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
151 |
| 637 | MACHINISTS | 50.0% |
0.0% |
0.0% |
0.0% |
50.0% |
9 |
| 683 | ELECTRICAL AND ELECTRONIC EQUIPMENT ASSEMBLERS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
164 |
| 689 | INSPECTORS, TESTERS, AND GRADERS | 9.4% |
0.0% |
0.0% |
0.0% |
90.6% |
831 |
| 709 | GRINDING, ABRADING, BUFFING, AND POLISHING MACHINE OPERATORS | 11.5% |
0.0% |
0.0% |
0.0% |
88.5% |
249 |
| 723 | METAL PLATING MACHINE OPERATORS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
32 |
| 777 | MISCELLANEOUS MACHINE OPERATORS, N.E.C. | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
135 |
| 785 | ASSEMBLERS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
106 |
| 796 | PRODUCTION INSPECTORS, CHECKERS, AND EXAMINERS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
117 |
| 797 | PRODUCTION TESTERS | 40.8% |
0.0% |
0.0% |
0.0% |
59.2% |
59 |
| SUBTOTAL | 18.4% |
0.0% |
2.3% |
0.0% |
79.1% |
6,070 | |
| Code | Occupation Description (1980) | No Control |
Resp Prot |
Other PPE |
Vent |
Other Control |
Exposures |
| 216 | ENGINEERING TECHNICIANS, N.E.C. | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
935 |
| 225 | SCIENCE TECHNICIANS, N.E.C. | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
38 |
| 235 | TECHNICIANS, N.E.C. | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
116 |
| 779 | MACHINE OPERATORS, NOT SPECIFIED | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
667 |
| 785 | ASSEMBLERS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
186 |
| 796 | PRODUCTION INSPECTORS, CHECKERS, AND EXAMINERS | 5.3% |
0.0% |
0.0% |
0.0% |
94.7% |
1,337 |
| 797 | PRODUCTION TESTERS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
23 |
| SUBTOTAL | 2.1% |
0.0% |
0.0% |
0.0% |
97.8% |
3,302 | |
| Code | Occupation Description (1980) | No Control |
Resp Prot |
Other PPE |
Vent |
Other Control |
Exposures |
| 059 | ENGINEERS, N.E.C. | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
693 |
| 216 | ENGINEERING TECHNICIANS, N.E.C. | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
429 |
| 523 | ELECTRONIC REPAIRERS, COMMUNICATIONS AND INDUSTRIAL EQUIPMENT | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
109 |
| 677 | OPTICAL GOODS WORKERS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
826 |
| 796 | PRODUCTION INSPECTORS, CHECKERS, AND EXAMINERS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
182 |
| SUBTOTAL | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
2,239 | |
| Code | Occupation Description (1980) | No Control |
Resp Prot |
Other PPE |
Vent |
Other Control |
Exposures |
| 235 | TECHNICIANS, N.E.C. | 100.0% |
0.0% |
0.0% |
0.0% |
0.0% |
12 |
| 515 | AIRCRAFT MECHANICS, EXC. ENGINE | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
38 |
| 653 | SHEET METAL WORKERS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
120 |
| 783 | WELDERS AND CUTTERS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
17 |
| SUBTOTAL | 6.4% |
0.0% |
0.0% |
0.0% |
93.5% |
187 | |
| Code | Occupation Description (1980) | No Control |
Resp Prot |
Other PPE |
Vent |
Other Control |
Exposures |
| 216 | ENGINEERING TECHNICIANS, N.E.C. | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
89 |
| SUBTOTAL | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
89 | |
| Code | Occupation Description (1980) | No Control |
Resp Prot |
Other PPE |
Vent |
Other Control |
Exposures |
| 045 | METALLURGICAL AND MATERIALS ENGINEERS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
29 |
| 057 | MECHANICAL ENGINEERS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
513 |
| 069 | PHYSICISTS AND ASTRONOMERS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
14 |
| 073 | CHEMISTS, EXCEPT BIOCHEMISTS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
488 |
| 078 | BIOLOGICAL AND LIFE SCIENTISTS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
15 |
| 213 | ELECTRICAL AND ELECTRONIC TECHNICIANS | 50.0% |
0.0% |
0.0% |
0.0% |
50.0% |
1,047 |
| 216 | ENGINEERING TECHNICIANS, N.E.C. | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
3,366 |
| 224 | CHEMICAL TECHNICIANS | 22.1% |
0.0% |
0.0% |
0.0% |
77.9% |
4,418 |
| 225 | SCIENCE TECHNICIANS, N.E.C. | 100.0% |
0.0% |
0.0% |
0.0% |
0.0% |
73 |
| 235 | TECHNICIANS, N.E.C. | 25.3% |
0.0% |
0.0% |
0.0% |
74.7% |
2,844 |
| 689 | INSPECTORS, TESTERS, AND GRADERS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
156 |
| 735 | PHOTOENGRAVERS AND LITHOGRAPHERS | 50.0% |
0.0% |
0.0% |
0.0% |
50.0% |
2,052 |
| SUBTOTAL | 22.1% |
0.0% |
0.0% |
0.0% |
77.8% |
15,015 | |
| Code | Occupation Description (1980) | No Control |
Resp Prot |
Other PPE |
Vent |
Other Control |
Exposures |
| 518 | INDUSTRIAL MACHINERY REPAIRERS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
1,190 |
| SUBTOTAL | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
1,190 | |
| Code | Occupation Description (1980) | No Control |
Resp Prot |
Other PPE |
Vent |
Other Control |
Exposures |
| 026 | MANAGEMENT ANALYSTS | 0.0% |
0.0% |
50.0% |
0.0% |
50.0% |
657 |
| 049 | NUCLEAR ENGINEERS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
7 |
| 069 | PHYSICISTS AND ASTRONOMERS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
7 |
| 083 | MEDICAL SCIENTISTS | 0.0% |
0.0% |
49.8% |
0.0% |
50.2% |
224 |
| 084 | PHYSICIANS | 3.6% |
0.0% |
45.9% |
0.0% |
50.5% |
22,844 |
| 085 | DENTISTS | 3.3% |
0.0% |
0.0% |
0.0% |
96.7% |
1,690 |
| 095 | REGISTERED NURSES | 4.0% |
0.0% |
45.1% |
0.0% |
50.9% |
60,151 |
| 098 | INHALATION THERAPISTS | 0.0% |
0.0% |
53.9% |
0.0% |
46.1% |
1,873 |
| 105 | THERAPISTS, N.E.C. | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
73 |
| 203 | CLINICAL LABORATORY TECHNOLOGISTS AND TECHNICIANS | 7.2% |
0.0% |
51.1% |
0.0% |
41.7% |
13,866 |
| 204 | DENTAL HYGIENISTS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
85 |
| 206 | RADIOLOGIC TECHNICIANS | 4.7% |
0.0% |
43.1% |
0.0% |
52.1% |
116,613 |
| 207 | LICENSED PRACTICAL NURSES | 0.0% |
0.0% |
11.5% |
0.0% |
88.5% |
7,442 |
| 208 | HEALTH TECHNOLOGISTS AND TECHNICIANS, N.E.C. | 1.3% |
0.0% |
46.9% |
0.0% |
51.8% |
8,533 |
| 213 | ELECTRICAL AND ELECTRONIC TECHNICIANS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
28 |
| 225 | SCIENCE TECHNICIANS, N.E.C. | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
306 |
| 235 | TECHNICIANS, N.E.C. | 0.0% |
0.0% |
18.5% |
0.0% |
81.5% |
1,618 |
| 379 | GENERAL OFFICE CLERKS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
270 |
| 445 | DENTAL ASSISTANTS | 100.0% |
0.0% |
0.0% |
0.0% |
0.0% |
107 |
| 446 | HEALTH AIDES, EXCEPT NURSING | 0.0% |
0.0% |
12.2% |
0.0% |
87.8% |
254 |
| 447 | NURSING AIDES, ORDERLIES, AND ATTENDANTS | 0.0% |
0.0% |
32.1% |
0.0% |
67.9% |
7,320 |
| 449 | MAIDS AND HOUSEMEN | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
397 |
| 633 | SUPERVISORS, PRODUCTION OCCUPATIONS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
40 |
| 678 | DENTAL LABORATORY AND MEDICAL APPLIANCE TECHNICIANS | 100.0% |
0.0% |
0.0% |
0.0% |
0.0% |
35 |
| 735 | PHOTOENGRAVERS AND LITHOGRAPHERS | 0.0% |
0.0% |
0.0% |
0.0% |
100.0% |
79 |
| 774 | PHOTOGRAPHIC PROCESS MACHINE OPERATORS | 0.0% |
0.0% |
50.0% |
0.0% |
50.0% |
1,161 |
| SUBTOTAL | 4.0% |
0.0% |
42.5% |
0.0% |
53.3% |
245,680 | |
| TOTAL | 4.8% |
0.0% |
41.4% |
0.0% |
53.5% |
325,418 | |
| RELATED PAGES: Estimates by SIC, Estimates by Occupation, Estimates by Occupation within SIC | |||||||
| ABBREVIATIONS: Resp Prot = Respiratory Protection Other PPE = Personal Protective Equipment Other Than Respiratory Protection Vent = Ventilation | |||||||
*(1) The estimates for each occupation apply only to the 3- and 4-digit SICs surveyed within the 2-digit SIC where the agent was observed. Not all SICs were surveyed, and not all agents were observed in all surveyed SICs. (2) When using the estimated numbers of exposures, standard errors associated with estimates should be considered. (3) Potential exposures to a chemical agent are categorized as actual (i.e., the surveyor observed the use of the specific agent) or tradename (i.e., the surveyor observed the use of a tradename product known to contain the specific agent). The estimates presented in the table combine both categories. (4) For a given occupation, the estimated number of potential exposures is not necessarily equal to the estimated total number of potentially exposed workers. For example, a worker may be exposed to the same agent from multiple sources; thus, it is not the worker that is controlled but the exposure. (5) The presence or absence of controls does not imply that controls are necessary or required. The estimates and the controls are strictly based on observations associated with potential exposures.