Area C

Area C, north of Pajarito Road near TA-50, became inactive April 8, 1974. Its history of use covers 26 years. There are seven pits within the area, one of which was reserved exclusively for the disposal of non-radioactive hazardous chemical wastes and 108 shafts; none of which are greater than 1m (3ft) in diameter and 7.6m (25ft) deep. Area C is the first burial ground for which detailed records were kept. Few Studies related to environmental monitoring have been conducted in Area C.

The history of Area C extends from may 7, 1948, the date the first pit was started, through April 18, 1974, the date the last shaft was filled and plugged with concrete. It is sometimes felt that the the last routine  radioactive contaminated waste placed in area C, December 1958, marks the closing of area C and the opening  of Area G. Neither idea is true. Area G pits had received non routine radioactive waste before that date and area C pits continued to receive non routine radioactive contained waste until Pit 6 was filled august 959 and Pit 5 was filled November or December 1964. Since quarterly and annual reports on solid radioactive waste disposal fail to mention Area C after 1968, it can be assumed that the area was not in regular use pats that time. The plugins of the last area C shaft, shaft 89, On April 1974, marked the formal closing of the area.

Type of Waste

During the pit history of Area C, hazardous chemicals and unconfined classified materials were buried with radioactive contaminated materials.

Hazardous Chemical Area in Area C

As pit use was phasing out in area C and beginning in area G, the idea of separate disposal for hazardous nonradioactive chemicals (which were responsible through the years for many fires in the disposal area) was accepted.

Location:  Technical Area (TA) -50

Period of use:

Pits (6):  June 1948 to December 1964

Shafts (107):  1958 to April 1974

Size:  11.8 acres

Number and type of disposal units:

Pits 1- 4:  610 by 40 feet

Pit 5:  705 by 110 feet by about 18 feet

Pit 6:  505 by 100 feet by about 23 feet

Chemical pit:  180 by 25 feet by about 12 feet

Vary between 1 to 2 feet in diameter, and 10 to 25 feet deep

Specific wastes and quantities:

Estimated Volume: 3,186,000 ft3 of TRU waste

Pits contain, as of January 1973:
25 Curies (Ci) of uranium
26 Ci of plutonium-239
149 Ci of americium-241

Shafts contain:
49,136 Ci of tritium
40 Ci sodium-22
20 Ci of cobalt-60
31 Ci of strontium-90
5 Ci of uranium-233
50 Ci fission products
200 Ci of induced activity
Also contains quantities of mercury, copper, cobalt, boron, beryllium, and silver. (2)

Potential environmental impacts:

Lies near Ten-Site Canyon New Mexico Environment Department’s (NMED) Hazardous and Radioactive Material Bureau (HRMB) ranks this MDA as an area with a high probability of contaminant mobilization and a moderate to high potential of release to the groundwater.


Figure B-5 has been removed due to illegibilty.


Rogers, Margaret Anne, History and Environmental Setting of Los Alamos Scientific Laboratory Near- Surface Land Disposal Facilities for Radioactive Wastes (Areas A, B, C, D, E, F, G, and T).
June 1977.