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Medical Exam Requirements



The Fred Young Submillimeter Telescope (FYST) is located at 5,600 meters above sea level (masl) near the summit of Cerro Chajnantor, a remote location in the Atacama desert of northern Chile.  The power generation facility is located near the base of Cerro Chajnantor at an altitude of ~4,850 masl.

The information on this web page contains a meaningful outline of medical clearance requirements for most people, but it does not list all variations and possible reporting details.  See the Safety Policy page for a complete listing of all requirements and obligations.


Working at high altitude in Chile (defined under Chilean labor law as work above 3,000 masl) requires a medical clearance from a doctor.  Working at extreme altitude (defined as work above 5,500 masl) requires an additional medical clearance.  Once medically cleared to work at high or extreme altitude, individuals are subject to strict regulations regarding the amounts of time they are allowed to work at high and extreme altitude, and individuals must also comply with several pre- and post-work requirements regarding training, acclimatization, health monitoring, and the use of personal protective equipment.  No person or contractor without the required documentation and training will be allowed access to CCAT-controlled high or extreme altitude facilities.

  • All individuals needing to work at a CCAT-controlled high or extreme altitude site must consult their physicians to verify there are no medical conditions that make it inadvisable to work at high or extreme altitude.
  • The designated sponsoring institution shall pay for the medical exam(s).  In some cases, CCAT Observatory Inc. may pay for or reimburse a sponsoring institution for the exam(s), but this must be approved in advance by the CCAT Project Manager, or other authorized person in the CCAT Project Office. 
  • Medical clearances for high and extreme altitude are valid for a maximum of 365 days.  The clearance must be dated on the day it is issued by the examining doctor.  On day 366, an individual will no longer be cleared to access high or extreme altitude sites until a new and current medical clearance letter is received.
  • NOTE:  All contracts requiring work at CCAT-controlled high or extreme altitude sites MUST be issued or approved by the CCAT Project Office as these contracts require contractors be informed of all medical and safety requirements and often must contain specific insurance and liability clauses.
  • For foreign nationals, it is each individual's responsibility to have the required medical exam(s) and clearance letter before arrival in Chile.  NOTE:  for individuals intending to travel to extreme altitude (>5,500 masl), some exams may need to be repeated by a licensed physician in Chile in order to be accepted by the Health Officials in Region II.  As such, please coordinate with the CCAT Project Office well in advance of your actual visit so that arrangements can be made.
  • For people located in Chile, it is the individual's responsibility to have the required medical exam(s) and clearance letter before arranging travel to the Atacama region.
  • No one associated with CCAT will knowingly escort or otherwise enable any other individual to travel above 3,000 masl in the Atacama region without the appropriate medical clearance.

Medical Protocols for Working in High Altitude

  •  CCAT follows the ACHS (Asociación Chilena de Seguridad) norm for the medical examinations
  •  Physical Exam Battery
    • Routine physical exam (including medical history, contraindications, Body Mass Index) plus:
    • Resting heart rate
    • Blood pressure, plus total/HDL cholesterol ratio
    • Cholesterol (LDL, HDL, VLDL, Total)
    • Creatinine
    • Electrocardiogram, Resting
    • Lake Louise Survey
    • Framingham Index
    • Glucose (Glicemia)
    • Hemoglobin
    • Posteroanterior (PA) chest X-ray (if indicated, or requested)
    • Triglycerides
    • Other tests, if recommended by the consulting physician (i.e., Basal Spirometry)


Additional Protocols for Working at Extreme Altitude

  • All required High Altitude exams, but the clearance letter must be signed a physician with Extreme Altitude medical training recognized by the Health Officials in Region II of Chile.  This may require the exam(s) to be accomplished in Chile.  Please contact the CCAT Project Office for details.
  • A stress Electrocardiogram
  • A hypoxia tolerance test.  Note, this exam must be accomplished at a recognized facility in Chile.  Contact the CCAT Project Office for details.

Absolute Contraindications

According to ACHS, the following conditions are qualified as absolute contraindications for altitude exposure:

  • Pregnancy
  • Kidney transplants or kidney failure (moderate or severe)
  • Record of heart failure
  • Record of vascular encephalic failure
  • Epilepsy with convulsions
  • Insulin dependent diabetes (when location of the work is an isolated place)

Relative Contraindications

Relative contraindications are temporary conditions, which are modifiable on a short or medium term (6 months) through control of the pathology or risk factor. Once the following are modified, ascent may be authorized:

  • Any chronic unbalanced pathology
  • Body mass index of greater than or equal to 35 (weight in kilograms/height squared in meters)
  • Moderate or severe cholesterol levels LDL/HDL>3.5 or triglycerides > 500 mg/dl
  • Hemoglobin over 18.7 gr/dl in men, and over 18 gr/dl in women
  • Severe anemia with hemoglobin less than 8 grams
  • Hyptertension with diastolic pressure >90 mm hg


  • All Medical Clearance Letters must be submitted to the CCAT Project Office's designated Safety Officer. 
  • Letters must indicate that all required medical tests were accomplished and no absolute or relative contraindications that would prevent Work at high or extreme altitude were noted. 
  • The letter must be dated, list the full name of the person who was examined, and signed by a licensed medical doctor along with appropriate contact information. 
  • If an individual's clearance letter contains private medical information, please coordinate with the CCAT Project Office prior to forwarding the letter.  NOTE: for individuals who are receiving medical clearance to Work at extreme altitude, a copy of this letter and any associated documentation will be sent to the Health SEREMI of Region II.  The Office of the Health SEREMI maintains their record sets in accordance with Chilean national privacy laws.  These laws provide for data privacy, but they are not exact equivalents to American HIPAA and European GDPR safeguards.  An individual submitting medical clearance to work at a CCAT-controlled facility must understand their records in Chile will be treated according to Chilean law.