NASA-STD-3001 Technical Brief

Relevant Technical 

Requirements

Spaceflight 

Toxicology

OCHMO-TB-015

Rev B

NASA-STD-3001 Volume 1, Rev C

[V1 3003] In-Mission Preventive Health Care

[V1 3004] In-Mission Medical Care

[V1 5001] Medical Training

[V1 5002] Crewmember Training

NASA-STD-3001 Volume 2, Rev D

[V2 4015] Aerobic Capacity 

[V2 6001] Trend Analysis of Environmental 

Data

[V2 6002] Inert Diluent Gas

[V2 6004] Nominal Vehicle/Habitat Carbon 

Dioxide Levels 

[V2 6023] Trace Constituent Monitoring and 

Alerting

[V2 6024] Combustion Monitoring and 

Alerting

[V2 6025] Contamination Monitoring and 

Alerting

[V2 6051] Water Contamination Control

[V2 6046] Water Quality Monitoring

[V2 6109] Water Quantity

[V2 6047] Toxic Hazard Level Three

[V2 6048] Toxic Hazard Level Four

[V2 6049] Chemical Decomposition

[V2 6050] Atmosphere Contamination Limit

[V2 6052] Particulate Matter

[V2 6153] Celestial Dust Monitoring

[V2 6053] Lunar Dust Contamination

[V2 6062] Availability of Environmental 

Hazards Information

Executive Summary

Safe, breathable air is essential for crew 

health. Human spaceflight has experienced 

toxicological events ranging in severity from 

trivial to life-threatening.

Toxic exposure to chemical contaminants can 

originate from system leaks, payload leaks, 

pyrolysis of polymeric materials, off-gassing of 

polymeric materials, use of utility compounds, 

propellant entry, microbial products, and 

human metabolism.

To ensure crew safety, NASA has developed a 

set of spaceflight-specific air quality guidelines 

called Spacecraft Maximum Allowable 

Concentrations (SMACs) to define levels to 

which air pollutants must be controlled to 

ensure no adverse effects. Furthermore, the 

system must include the ability to 

control/prevent contamination, monitor 

contaminants, provide crew with appropriate 

Personal Protective Equipment (PPE) and 

mitigate contamination, including cleaning 

affected surfaces and treating crewmembers, 

should an event occur.
NASA-STD-3001 Technical Brief

OCHMO-TB-015 Spaceflight Toxicology

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Relevant Technical 

Requirements

Executive Summary (continued)

2

NASA-STD-3001 Volume 2, Rev D

[V2 6063] Contamination Cleanup

[V2 7043] Medical Capability

[V2 7069] Labeling of Hazardous Waste

[V2 7080] Particulate Control

[V2 7082] Surface Material Cleaning 

[V2 9024] Fluid/Gas Release

[V2 9025] Fluid/Gas Isolation

[V2 9026] Fluid/Gas Containment

[V2 9053] Protective Equipment

[V2 9054] Protective Equipment Use

[V2 11001] Suited Donning and Doffing

10/30/2023

Rev B

NASA Exposure Guidelines: 

Spacecraft Maximum 

Allowable Concentrations for 

Selected Airborne 

Contaminants 

NASA astronaut Reid Wiseman works with the Total 

Organic Carbon Analyzer (TOCA). Photo: NASA
NASA-STD-3001 Technical Brief

OCHMO-TB-015 Spaceflight Toxicology

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Background

Sources of Toxic Chemicals in Spacecrafts

• Compounds used in systems (e.g., 

ammonia, ethylene glycol, Freon 218)

• Payload chemicals (e.g., fixatives)

• Off-gassed products (e.g., 

formaldehyde)

• Batteries (electrolytes and fire hazard)

• Products of corrosion 

• External contaminants (e.g., Fuel 

Oxidizer Reaction Product (FORP))

• Operational anomalies/hardware 

failures and repair (e.g., SKV Heater)

• Thermal degradation of electronic 

components and other fires

• The threat to crew health may occur 

as a result of inhalation, ingestion, or 

dermal/ocular contact with the 

contaminants.

• Contact exposure to chemicals can 

cause injury to the skin and eyes; 

inhalation can damage the lungs; 

ingestion can damage the digestive 

tract; and any method of exposure can 

have a systemic effect that could be 

hazardous depending on the chemical 

and amount.

• The effects of exposure to toxic 

hazards can vary in type and severity. 

• The JSC toxicologists establish 

guidelines for safe and acceptable 

levels of individual chemical 

contaminants in spacecraft air 

(SMACs) to provide guidance on 

allowable chemical exposures during 

nominal operations and emergency 

situations.

10/30/2023

Rev B 3
NASA-STD-3001 Technical Brief

OCHMO-TB-015 Spaceflight Toxicology

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Exposure Guidelines (SMACs)

SMACs are set to protect healthy crewmembers from adverse effects, significant discomfort, or 

degradation in performance resulting from continuous exposure to airborne substances (such as gas, 

vapor, or aerosol).

Guidelines for Developing SMACs

When developing appropriate exposure criteria, experts take into account:

• Microgravity environment: Deposition of particles, lung function, and the toxic potential of inhaled 

particles may be different under microgravity conditions than under full gravity conditions, as on Earth.

• Radiation:

 Due to the potential interaction of radiation and benzene leading to leukemia (Khan-Mayberry, 

2008) and the relatively high radiation environment of space, SMACs for benzene are set at lower 

levels of acceptable exposure.

• Astronaut physiological and 

psychological conditions:

 Loss of muscle and bone mass

 Altered immune system

 Cardiovascular changes

 Decreased red blood cell mass

 Altered nutritional requirements

 Behavioral changes from stress

 Fluid shift in the body

 Altered hormonal status

 Altered drug metabolism

Background

10/30/2023

Rev B 4

Length of Exposure Exposure Guidelines (SMACs)

1 and 24 hours Guidelines intended to allow performance of specific tasks during emergency 

conditions lasting up to 24hr. Exposure to 1-or 24-hr SMACs will not cause 

serious or permanent effects but may cause reversible effects that do not 

impair judgment or interfere with proper responses to emergencies such as 

fires or accidental releases. Short-term SMACs are intended for off-nominal 

events and should not be used for system design or evaluation of routine 

exposures.

7, 30, and 180 days Guidelines intended to avoid adverse health effects (either immediate or 

delayed) and to avoid degradation in crew performance with continuous 

exposure in a closed environment for various durations.

1000+ days Guidelines intended for longer space missions beyond low Earth orbit and to 

other celestial bodies. 

Relevant Technical Requirement

[V2 6050] Atmosphere Contamination Limit The 

system shall limit gaseous pollutant accumulation 

in the habitable atmosphere below individual 

chemical concentration limits specified in JSC20584, Spacecraft Maximum Allowable 

Concentrations for Airborne Contaminants 

(SMACs).

From: NASA-STD-3001 Volume 2, Rev D
NASA-STD-3001 Technical Brief

OCHMO-TB-015 Spaceflight Toxicology

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Reference Data

Spacecraft-Atmosphere Contamination Sources

10/30/2023

Rev B 5

Release of 

toxic 

substances 

Leak Spill Fire

Carbon Dioxide (CO2)

• What is it: CO2 is a product of respiration. Concentrations increase in confined areas, especially if 

they are poorly ventilated.

• Sources: Human and animal payload metabolism/expiration, increased production during exercise.

• How does it affect crew health: Overexposure to CO2 can cause headaches of varying severity, vision 

changes, nausea, and unconsciousness in severe overexposure.

Carbon Monoxide (CO)

• What is it: CO is an odorless, colorless gas that is 

produced by incomplete combustion of 

carbon-containing materials (Penny 2000a).

• Sources: In spaceflight, CO production will most 

likely be associated with a fire.

• How does it affect crew health: The most common 

symptoms of CO poisoning includes headache, 

dizziness, weakness, upset stomach, vomiting, chest 

pain, and confusion. These symptoms depend on a 

combination of the airborne concentration of CO, the 

activity level of the exposed individual, and the 

length of exposure.

CO Toxicity Symptoms 

Reference OCHMO-TB-004 Carbon Dioxide (CO2) 
NASA-STD-3001 Technical Brief

OCHMO-TB-015 Spaceflight Toxicology

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Reference Data

10/30/2023

Rev B 6

Freons and Other Halocarbons

• What is it: Halocarbons are mostly human-made gases consisting of both carbon and at least one of 

the halogens (fluorine, chlorine, iodine, and bromine).

• Source: Crewmembers could be exposed in the event of a leak.

• How does it affect crew health: This group of halocarbons has very low toxicity. The primary effect of 

this class of compounds is cardiac sensitization leading to rhythm disturbances. This effect is generally 

noted only at concentrations above 1%.

Ammonia

• What is it: Ammonia is a water-soluble gas with a characteristic pungent smell.

• Source: Ammonia accumulates slowly in spacecraft atmospheres as a result of human metabolism. It is 

also used in active thermal control of the U.S. Segment of the ISS and Orion. It can enter the cabin and 

expose the crew in a few ways:

 Leaks in the cabin through the interface heat exchanger

 Compromised structural integrity from a hard landing causing a leak in the cabin

 Vented ammonia brought in by the snorkel fan

• How does it affect crew health: Inhalation of lower concentrations can cause coughing and nose and 

throat irritation. Exposure to high levels of ammonia in air causes immediate burning of the nose, 

throat, and respiratory tract which might lead to respiratory distress or failure.

Estimated toxic response to acute exposures to 

ammonia vapors

Ammonia mask fitted with ammonia cartridges
NASA-STD-3001 Technical Brief

OCHMO-TB-015 Spaceflight Toxicology

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Reference Data

10/30/2023

Rev B 7

Airborne Carcinogens

• What is it: Volatile contaminants that may present an increased cancer risk with elevated exposure 

over time.

• Source: Most carcinogens originate from materials off-gassing. Common carcinogens monitored in 

spacecrafts and their primary sources are:

• Acetaldehyde: Human metabolism, materials off-gassing

• Benzene: Materials off-gassing, polymer pyrolysis

• 1,2-dichloroethane: Hardware off-gassing 

• Formaldehyde: Hardware off-gassing 

• Furan: Hardware off-gassing, heating of organic materials

• Isoprene: Human metabolism, plants 

• How does it affect crew health: Acetaldehyde, benzene, and 1,2-dichloroethane have been shown to 

react with DNA and to cause mutations. Formaldehyde, furan, and isoprene cause cancer by 

epigenetic mechanisms. Most spaceflight exposures are not adequate in concentration or duration to 

present a significant increase in cancer risk to crew.

Noxious Compounds

• What is it: Malodorous compounds.

• Source: Noxious sulfur compounds can be produced by biological waste that is stored for long periods 

or as a by-product of human metabolism.

• How does it affect crew health: Noxious compounds may result in secondary health effects, such as 

nausea or headache, following exposure.

Profile of formaldehyde in the U.S. Lab 

and Russian Service Module over the life 

of ISS

Formaldehyde

• What is it: Formaldehyde is a colorless 

gas with a pungent and suffocating 

smell.

• Source: It can enter space vehicles 

through leakage of fixatives from 

payload experiments, off-gassing of 

hardware, thermo-degradation of 

certain polymeric materials, and 

incomplete oxidation of contaminants in 

the environmental control system.

• How does it affect crew health: It is an 

irritant to the eyes and respiratory 

system, and after prolonged exposure, is 

carcinogenic.
NASA-STD-3001 Technical Brief

OCHMO-TB-015 Spaceflight Toxicology

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Reference Data

10/30/2023

Rev B 8

Airborne Particles and Dust

• What is it: Particles that are floating in the air.

• Source: Airborne particles could come from 

desquamation of skin cells from crewmembers, 

flaking of paint, release of lint from fabrics, and 

handling of food. Particles are also released from 

smoldering or fire events and are used for fire 

warning via smoke detection. Surface dust on 

celestial bodies, such as the Moon or Mars, may 

also contaminate spacecraft vehicles.

• How does it affect crew health: Microgravity will 

cause the particles to float, increasing the 

likelihood that they will enter the eyes and 

respiratory systems of crewmembers and cause 

irritation. 

Combined Exposures

• Spacecraft atmospheres are a complex mixture of various individual contaminants.

• To address exposure to multiple, rather than individual compounds, JSC Toxicology utilizes a hazard 

index or T-value. Air is deemed safe if the combined hazard index of all compounds with similar health 

endpoints is <1.

Crewmember Shannon Walker using a vacuum 

during ISS routine housekeeping

Apollo 17 astronaut Harrison Schmitt 

retrieves lunar samples during his 

December 1972 mission, his spacesuit 

dirtied by clinging lunar dust Lunar dust

Reference OCHMO-TB-011 Lunar Dust 
NASA-STD-3001 Technical Brief

OCHMO-TB-015 Spaceflight Toxicology

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Reference Data

10/30/2023

Rev B 9

Examples of Toxicological Events During Spaceflight 

Apollo 1 (1967): Fire on the pad at the Kennedy Space Center 

resulted in the death of 3 crewmembers in part due to toxic 

exposure to combustion products that were thought to 

include carbon monoxide, carbon dioxide, and irritant gases.

Apollo-Soyuz (1975): The Apollo capsule became highly 

polluted with nitrogen tetroxide during descent of the 

capsule through the atmosphere. The crew experienced 

respiratory symptoms and delayed release of fluid into the 

lungs. They were treated with oral steroids and released 

from the hospital 6 days post-landing.

STS-40 (1991): Motor from refrigerator/freezer produced 

formaldehyde during overheating. This irritating compound 

and others thought to be produced in the event seriously 

polluted the spacecraft atmosphere.

STS-55 (1993): The waste management system failed; 

therefore, waste was being stored in contingency waste bags. 

The crew reported a noxious odor emanating from the bags. 

An air sample analyzed later on the ground revealed that 

methyl sulfide compounds were being produced inside the 

bags. 

Mir (1997): A solid fuel oxygen generator caught fire and 

burned in the cabin openly for at least a minute. Air samples 

revealed that dangerous combustion toxicants, such as 

carbon monoxide, remained at somewhat elevated but safe 

levels. 

ISS/STS (1998): Toxic ammonia leak during EVA 1 on the 

mission. A defective quick-disconnect valve allowed 5% of 

the ammonia cooling supply to escape into space. The 

escaping ammonia froze on the spacesuit of an astronaut as 

he struggled to close the valve. Remains of the solid fuel oxygen 

generator that combusted aboard 

Mir space station in 1997. 

Normal Roentgenogram of the lung 

(left) and one from an Apollo 

astronaut accidentally exposed to 

propellants during capsule descent 

(right). The second figure suggests 

fluid infiltrate of the lungs. 

Motor from STS-40 Orbiter 

Refrigerator/Freezer 

that produced formaldehyde 

during overheating. 
NASA-STD-3001 Technical Brief

OCHMO-TB-015 Spaceflight Toxicology

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Application

10/30/2023

Rev B 10

Spacecraft designs must control/prevent contamination, monitor contaminants, and mitigate 

contamination, including cleaning affected surfaces and treating crewmembers, should an event occur.

Implementation of Requirements

• NASA-STD-3001 technical requirements and SMACs need to be implemented in spacecraft 

development.

Materials Selection/Off-Gas Testing

• The habitable volume must contain chemicals that are hazard level 3 or below. Chemicals that are 

hazard level 4 must be prevented from entering the habitable volume. These levels depend on the 

inherent toxicity of the material, the amount of material that could be released into the atmosphere, 

the volume into which the release could occur, the nature of the injury (contact or systemic), and 

containability of a release.

Relevant Technical Requirements

[V2 6047] Toxic Hazard Level Three

[V2 6048] Toxic Hazard Level Four

From: NASA-STD-3001 Volume 2, Rev D

 Large volumes of relatively nontoxic material such 

as ammonia can be toxic hazard level 4, whereas 

small volumes of extremely hazardous materials 

such as thionyl chloride (found in some types of 

batteries) can also be toxic hazard level four.
NASA-STD-3001 Technical Brief

OCHMO-TB-015 Spaceflight Toxicology

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Application

10/30/2023

Rev B 11

Toxicological Assessments 

• Potentially toxic substances (gases, liquids, particles) that may be released into habitable/free volume 

must be assessed and provide appropriate mitigation and response strategies.

• All components and other materials to be carried on board must be tested to identify and quantify 

(under test conditions) off-gassing compounds.

• All hardware/payloads that include liquids, gases, particles, gels, or biological materials must contain a 

label so that the crew and ground personnel can easily identify whether the payload contains any toxic, 

biological, or flammability hazards.

• Crewmembers must be briefed prior to the flight so that they can identify toxic hazard labels and 

educate them on experiments and systems containing known toxic hazards. To quickly identify potential 

contaminants within the spacecraft, all toxicological and environmental hazard information (e.g., 

Material Safety Data Sheets [MSDS]) must be accessible to the crew throughout the mission.

Air Filtration

• A reliable environmental control and life-support system (ECLSS) must be provided to maintain the 

environmental parameters within standards.

 ISS: The ISS ECLS system is designed to control temperature, humidity, and composition of spacestation air, including CO2 removal; water recovery; waste disposal; and detect and suppress fires. 

Monitoring

• Monitoring and alerting are 

required to identify when 

hazardous contaminants are 

detected and to alert the crew so 

they can take appropriate actions 

to maintain health and safety. 

• The type of monitoring that is 

needed and how often samples 

should be collected and analyzed 

depends greatly upon the mission 

length and vehicle architecture. 

Reference OCHMO-TB-002 

Environmental Control & 

Life Support System (ECLSS)
NASA-STD-3001 Technical Brief

OCHMO-TB-015 Spaceflight Toxicology

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Application

10/30/2023

Rev B 12

Real-Time Air Monitoring

• Monitoring systems must provide real-time capability for the 

measurement and display of atmospheric concentrations of toxic 

combustion; as well as automatic alerts/alarms when levels are 

outside of the safe value range.

• Real-time monitors give the crew and ground personnel access to 

real-time chemical constituents in the air. Some are broad-spectrum, 

while others target specific components:

 Compound specific analyzer for combustion products (CSA- CP)

 Carbon monoxide monitor (CDM)

 Air quality monitor (AQM) Combustion product analyzer

Carbon Monoxide monitor

ISS personal CO2 monitor

Relevant Technical Requirements

[V2 6022] Atmospheric Monitoring and Alerting Parameters The 

system shall alert the crew locally and remotely when 

atmospheric parameters, including atmospheric pressure, 

humidity, temperature, ppO2, and ppCO2 are outside safe limits.

[V2 6023] Trace Constituent Monitoring and Alerting The system 

shall monitor trace volatile organic compounds (VOCs) in the 

cabin atmosphere and alert the crew locally and remotely when 

they are approaching defined limits.

[V2 6024] Combustion Monitoring and Alerting The system shall 

monitor in real-time the toxic atmospheric components listed in 

Table 3, Recommended Combustion Product (CP) Monitoring 

Ranges, that would result from pre-combustion and combustion 

events in the ranges and with the accuracy and resolution 

specified in the table and alert the crew locally and remotely in 

sufficient time for them to take appropriate action.

[V2 6025] Contamination Monitoring and Alerting The system 

shall monitor and display atmospheric compound levels that 

result from contamination events, e.g., toxic release, systems 

leaks, or externally originated, before, during, and after an event 

and alert the crew locally and remotely in sufficient time for 

them to take appropriate action.

From: NASA-STD-3001 Volume 2, Rev D
NASA-STD-3001 Technical Brief

OCHMO-TB-015 Spaceflight Toxicology

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Application

10/30/2023

Rev B 13

Archival Air Monitoring

• Archival air samples are collected using "grab sample containers" 

(GSC) and formaldehyde badges.

 Grab sample containers: Since the Gemini program, 3 archival 

air samplings have been performed on spacecraft as an 

element of crew health and safety to verify air quality and 

ECLSS performance forensically. Various types of GSC have 

been used.

 Formaldehyde badges: Used for nominal sampling and can be 

used to detect formaldehyde in an area or adhered to a 

crewmember to detect personal exposures.

• Compound concentrations obtained by ground-based analyses of 

archival samples are compared with established requirements 

(SMACs) to assess the quality of the air during the mission. The 

processed data are then presented to the NASA toxicologist for a 

formal declaration on the air quality for the mission.

• For near-Earth mission lengths that extend to 6 months or more, air 

monitoring shifts to real-time monitors, with relatively few archival 

samples being collected and returned for later analysis.

• For missions beyond lower-Earth orbit, the system needs to provide 

the necessary tools for onboard sample analysis. 

Personal Protective Equipment (PPE)

• Generic PPE for moderate toxin releases and specialized PPE for 

severe releases must be available to crew on the spacecraft.

Formaldehyde badge (FMK)

Relevant Technical Requirements

[V2 9053] Protective Equipment Protective equipment shall be 

provided to protect the crew from expected hazards.

[V2 9054] Protective Equipment Use Protective equipment 

shall not interfere with the crew’s ability to conduct the 

nominal or contingency operations that the crew is expected to 

perform while employing the protective equipment, including 

communication among crewmembers and with ground 

personnel.

From: NASA-STD-3001 Volume 2, Rev D

NASA astronaut Terry Virts sits is one of the 

hatchways aboard the ISS. Crew typically wear 

PPE (mask, glasses, gloves) whenever opening a 

hatch following dynamic operations as a 

precaution.
NASA-STD-3001 Technical Brief

OCHMO-TB-015 Spaceflight Toxicology

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Back-Up

10/30/2023

Rev B 14
NASA-STD-3001 Technical Brief

OCHMO-TB-015 Spaceflight Toxicology

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Rev A  Rev B

• Updated information to be consistent with NASA-STD-3001 

Volume 1 Rev C and Volume 2 Rev D.

Original  Rev A

• Updated information to be consistent with NASA-STD-3001 

Volume 1 Rev B and Volume 2 Rev C.

Major Changes Between Revisions

10/30/2023

Rev B 15
NASA-STD-3001 Technical Brief

OCHMO-TB-015 Spaceflight Toxicology

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

NASA-STD-3001 Volume 1 Revision C

[V1 3003] In-Mission Preventive Health Care All programs shall provide training, in-mission capabilities, 

and resources to monitor physiological and psychosocial well-being and enable delivery of in-mission 

preventive health care, based on epidemiological evidence-based probabilistic risk assessment (PRA),

individual crewmember needs, clinical practice guidelines, flight surgeon expertise, historical review, 

mission parameters, and vehicle derived limitations. These analyses consider the needs and limitations

of each specific vehicle and design reference mission (DRM) with particular attention to parameters such 

as mission duration, expected return time to Earth, mission route and destination, expected radiation

profile, concept of operations, and more. In-mission preventive care includes, but is not limited to: (see 

NASA-STD-3001 Volume 1 Rev C for full technical requirement). 

[V1 3004] In-Mission Medical Care All programs shall provide training, in-mission medical capabilities, 

and resources to diagnose and treat potential medical conditions based on epidemiological evidencebased PRA, individual crewmember needs, clinical practice guidelines, flight surgeon expertise, historical 

review, mission parameters, and vehicle-derived limitations. These analyses consider the needs and 

limitations of each specific vehicle and design reference mission (DRM) with particular attention to 

parameters such as mission duration, expected return time to Earth, mission route and destination, 

expected radiation profile, concept of operations, and more. In-mission capabilities (including hardware 

and software), resources (including consumables), and training to enable in-mission medical care, and 

behavioral care, are to include, but are not limited to: (see NASA-STD-3001, Volume 1 Rev C for full 

standard).

[V1 5001] Medical Training Medical training shall be provided to crewmembers, flight surgeons (FSs), 

mission control support staff, and other ground support personnel (GSP).

[V1 5002] Crewmember Training Beginning with the crewmember candidate year, general medical 

training, including but not limited to, first aid, cardiopulmonary resuscitation (CPR), altitude physiological 

training, carbon dioxide exposure training, familiarization with medical issues, procedures of spaceflight, 

psychological training, toxicology, medical equipment, and supervised physical conditioning training shall 

be provided to the astronaut corps.

NASA-STD-3001 Volume 2 Revision D

[V2 4015] Aerobic Capacity The system shall be operable by crewmembers with the aerobic capacity as 

defined in NASA-STD-3001, Volume 1.

[V2 6001] Trend Analysis of Environmental Data The system shall provide environmental monitoring data 

in formats compatible with performing temporal trend analyses.

[V2 6002] Inert Diluent Gas Cabin atmospheric composition shall contain at least 30% diluent gas 

(assuming balance oxygen). 

[V2 6004] Nominal Vehicle/Habitat Carbon Dioxide Levels The system shall limit the average one-hour 

CO2 partial pressure (ppCO2) in the habitable volume to no more than 3 mmHg. 

[V2 6023] Trace Constituent Monitoring and Alerting The system shall monitor trace volatile organic 

compounds (VOCs) in the cabin atmosphere and alert the crew locally and remotely when they are 

approaching defined limits.

Referenced Technical Requirements

10/30/2023

Rev B 16

View the current versions of NASA-STD3001 Volume 1 & Volume 2 on the 

OCHMO Standards website
NASA-STD-3001 Technical Brief

OCHMO-TB-015 Spaceflight Toxicology

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

NASA-STD-3001 Volume 2 Revision D

[V2 6024] Combustion Monitoring and Alerting The system shall monitor in real-time the toxic 

atmospheric components listed in Table 6.2-3—Recommended Combustion Product (CP) Monitoring 

Ranges, that would result from pre-combustion and combustion events in the ranges and with the 

accuracy and resolution specified in the table, and alert the crew locally and remotely in sufficient time for 

them to take appropriate action. 

[V2 6025] Contamination Monitoring and Alerting The system shall monitor and display atmospheric 

compound levels that result from contamination events, e.g., toxic release, systems leaks, or externally 

originated, before, during, and after an event and alert the crew in sufficient time for them to take 

appropriate action.

[V2 6047] Toxic Hazard Level Three The system shall use only chemicals that are Toxic Hazard Level Three 

or below, as defined in JSC-26895, Guidelines for Assessing the Toxic Hazard of Spacecraft Chemicals and 

Test Materials, in the habitable volume of the spacecraft.

[V2 6048] Toxic Hazard Level Four The system shall prevent Toxic Hazard Level Four chemicals, as defined 

in JSC-26895, from entering the habitable volume of the spacecraft.

[V2 6049] Chemical Decomposition The system shall use only chemicals that, if released into the 

habitable volume, do not decompose into hazardous compounds that would threaten health during any 

phase of operations.

[V2 6046] Water Quality Monitoring The system shall provide the capability to monitor water quality and 

notify the crew locally and remotely when parameters are approaching defined limits.

[V2 6051] Water Contamination Control The system shall prevent potable and hygiene water supply 

contamination from microbial, atmospheric (including dust), chemical, and non-potable water sources to 

ensure that potable and hygiene water are provided.

[V2 6109] Water Quantity The system shall provide a minimum water quantity as specified in Table 6.3-

1—Water Quantities and Temperatures, for the expected needs of each mission, which should be 

considered mutually independent.

[V2 6050] Atmosphere Contamination Limit The system shall limit gaseous pollutant accumulation in the 

habitable atmosphere below individual chemical concentration limits specified in JSC-20584, Spacecraft 

Maximum Allowable Concentrations for Airborne Contaminants (SMACs). 

[V2 6052] Particulate Matter The system shall limit the habitable atmosphere particulate matter 

concentration for total dust to <3 mg/m3 with a crew generation rate of 1.33 mg/person-minute, and the 

respirable fraction of the total dust <2.5 μm (micrometer) in aerodynamic diameter to <1 mg/m3 with a 

crew generation rate of 0.006 mg/person-minute. 

[V2 6053] Lunar Dust Contamination The system shall limit the levels of lunar dust particles less than 10 

μm in size in the habitable atmosphere below a time weighted average of 0.3 mg/m3 during intermittent 

daily exposure periods that may persist up to 6 months in duration.

[V2 6062] Availability of Environmental Hazards Information The system shall provide toxicological and 

environmental hazard information in formats accessible by the crew throughout the mission

[V2 6063] Contamination Cleanup The system shall provide a means to remove or isolate released 

chemical and biological contaminants and to return the environment to a safe condition.

Referenced Technical Requirements

10/30/2023

Rev B 17

View the current versions of NASA-STD3001 Volume 1 & Volume 2 on the 

OCHMO Standards website
NASA-STD-3001 Technical Brief

OCHMO-TB-015 Spaceflight Toxicology

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

NASA-STD-3001 Volume 2 Revision D

[V2 6153] Celestial Dust Monitoring and Alerting The vehicle shall monitor celestial dust and alert the 

crew locally and remotely when they are approaching defined limits.

[V2 7043] Medical Capability A medical system shall be provided to the crew to meet the medical 

requirements of NASA-STD-3001, Volume 1.

[V2 7069] Labeling of Hazardous Waste The hazard response level (HRL) of all liquids, particles, gases, and 

gels shall be labeled on the outermost containment barrier in location(s) visible to crew.

[V2 7080] Particulate Control The system shall be designed for access, inspection, and removal of 

particulates that can be present before launch or that can result from mission operations.

[V2 7082] Surface Material Cleaning The system shall contain surface materials that can be easily cleaned 

and sanitized using planned cleaning methods.

[V2 9024 ] Fluid/Gas Release Hardware and equipment shall not release stored fluids or gases in a 

manner that causes injury to the crew.

[V2 9025 ] Fluid/Gas Isolation The system shall provide for the isolation or shutoff of fluids and gases in 

hardware and equipment.

[V2 9026] Fluid/Gas Containment The system shall provide for containment and disposal of fluids that 

might be released during operation or maintenance. 

[V2 9053] Protective Equipment Protective equipment shall be provided to protect the crew from 

expected hazards.

[V2 9054] Protective Equipment Use Protective equipment shall not interfere with the crew’s ability to 

conduct the nominal or contingency operations that the crew is expected to perform while employing the 

protective equipment, including communication among crewmembers and with ground personnel.

[V2 11001] Suited Donning and Doffing The system shall accommodate efficient and effective donning 

and doffing of spacesuits for both nominal and contingency operations.

Referenced Technical Requirements

10/30/2023

Rev B 18

View the current versions of NASA-STD3001 Volume 1 & Volume 2 on the 

OCHMO Standards website
NASA-STD-3001 Technical Brief

OCHMO-TB-015 Spaceflight Toxicology

NASA Office of the Chief Health & Medical Officer (OCHMO)

This Technical Brief is derived from NASA-STD-3001 and is for reference only.

It does not supersede or waive existing Agency, Program, or Contract requirements.

Reference List

10/30/2023

Rev B 19

1. Khan-Mayberry NN and James JT (2011). Space Toxicology: Toxicological Risk Management of Human Health 

during Space Exploration. General, Applied and Systems Toxicology, DOI: 10.1002/9780470744307.gat169

2. James JT. (2008). Health Effects of Atmospheric Contamination. Principles of Clinical Medicine for Space Flight, 

427-443. 

3. Freudenrich C. (2011). How is carbon dioxide eliminated aboard a spacecraft? HowStuffWorks. 

https://science.howstuffworks.com/carbon-dioxide-eliminated-aboard-spacecraft.htm.

4. Carbon Dioxide Control: Molecular Sieves. http://settlement.arc.nasa.gov/teacher/course/zeolite.htm

5. HSRB_CO2_Risk_RevPackage. (2018). Human Subjects Risk Board. NASA Internal Document.

6. James JT. (2011). A History of Space Toxicology Mishaps: Lessons Learned and Risk Management. SAE 

International Journal of Aerospace, 4(1): 577-583.

7. Perry JL and LeVan D. (2002). Air Purification in Closed Environments: An Overview of Spacecraft Systems. 

https://www.researchgate.net/publication/23903409_Air_Purification_in_Closed_Environments_An_Overview

_of_Spacecraft_Systems/download

8. Guidelines for Developing Spacecraft Maximum Allowable Concentrations for Space Station Contaminants. 

(2008). Committee on Toxicology National Research Council. National Academy Press.

https://www.nap.edu/read/21636/chapter/1

9. Khan-Mayberry N, James JT, Tyl R, Lam C. (2011). Space Toxicology: Protecting Human Health During Space 

Operations. International Journal of Toxicology, 30(1). 

10. James JT, et al. (2002). Environmental Monitoring Air Quality. 

https://www.researchgate.net/publication/237114268_Environmental_Monitoring_Air_Quality

11. NASA-STD-3001 Volume 2, Revision B. (2009). https://www.nasa.gov/sites/default/files/atoms/files/nasa-std3001_vol_2_rev_b.pdf

12. NRC. (1996). Spacecraft Maximum Allowable Concentrations for Selected Airborne Contaminants, Volume 2, 

National Academy Press, Washington, D.C. 

13. NRC. (1996). Spacecraft Maximum Allowable Concentrations for Selected Airborne Contaminants, Volume 3, 

National Academy Press, Washington, D.C.

14. NRC. (2000). Spacecraft Maximum Allowable Concentrations for Selected Airborne Contaminants, Volume 4, 

National Academy Press, Washington, D.C.

15. NRC. (2008). Spacecraft Maximum Allowable Concentrations for Selected Airborne Contaminants, Volume 5, 

National Academy Press, Washington, D.C.

16. Meyers VE, Garcia HD, and James JT. (2013). Safe Human Exposure Limits for Airborne Linear Siloxanes during 

Spaceflight. Inhalation Toxicology, 25(13): 735-746. 

17. Refinements to the Methods for Developing Spacecraft Exposure Guidelines. (2016). National Academy Press. 

https://www.nap.edu/catalog/21888/refinements-to-the-methods-for-developing-spacecraft-exposureguidelines

18. Romoser AA, Ryder VE, and McCoy JT. (2019). Spacecraft Maximum Allowable Concentrations for Manganese 

Compounds in Mars Dust. Aerospace Medicine and Human Performance, 90(8): 709-719. 

19. Scully RR, Garcia H, McCoy JT, Ryder VE. (2019). Revisions to Limits for Methanol in the Air of Spacecraft. 

Aerospace Medicine and Human Performance, 90(9): 807-812.

20. Guidelines for Developing Spacecraft Maximum Allowable Concentrations for Space Station Contaminants. 

(1992). National Academy Press. http://nap.edu/21636

21. Limero TF and Wallace WT. (2017). What Air and Water Quality Monitoring Is Needed to Protect Crew Health 

on Spacecraft? New Space, 5(2): 67-78.