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Physical / Chemical Properties:
CAS#: Sulfuric acid: 7664-93-9; Hydrogen peroxide: 7722-84-1
GHS Classification: Corrosive, Oxidizer
Molecular Formula: H
2
SO
4
and H
2
O
2
Form (physical state): Liquid
Color: Colorless
Piranha Solution 1 Date: 3/14/2014

Uses:
Piranha solution, also known as piranha etch, is a mixture of Sulfuric acid (H
2
SO
4
) and Hydrogen peroxide (H
2
O
2
), used to clean organic residues off substrates. Because the mixture is a strong oxidizer, it will remove most organic matter, and it will also hydroxylate most surfaces (add -OH groups), making them extremely hydrophilic (water compatible). Piranha solution is used frequently in the microelectronics industry, e.g. to clean photoresist residue from silicon wafers. The traditional piranha solution is a 3:1 mixture of Sulfuric acid and 30% Hydrogen peroxide.
The solution may be mixed before application or directly applied to the material, applying the Sulfuric acid first, followed by the peroxide. Piranha solutions are extremely energetic and may result in explosion or skin burns if not handled with extreme caution.
Piranha solution is very dangerous, being both strongly acidic and a strong oxidizer. Both liquid and vapour forms are extremely corrosive to skin and respiratory tract. Direct contact will create skin burns and will be extremely destructive to mucous membranes, upper respiratory tract and eyes. The Piranha solution is very energetic, exothermic, and potentially explosive. Mixing the solution is exothermic. The resultant heat can bring solution temperatures up to 120°C. Handle with care! When preparing the Piranha solution, always add the peroxide to the acid. One must allow the solution to cool reasonably before applying any heat. The sudden increase in temperature can also lead to violent boiling, or even splashing of the extremely acidic solution. Also, explosions may occur if the peroxide solution concentration is more than 50%. 30% peroxide in water solution is more reasonable. Piranha solution reacts violently with any organic materials. Avoid mixing with incompatible materials such as acids, bases, organic solvents (acetone, isopropyl alcohol) or nylon. Only use clean glass or Pyrex containers; Piranha solutions are not compatible with plastic.
Potential Health Effects:
Inhalation: Harmful if inhaled. Material is extremely destructive to the tissue of the mucous membranes and upper respiratory tract.
Skin: Harmful if absorbed through skin. Causes skin burns.
Eyes: Causes severe eye burns.
Ingestion: Harmful if swallowed.
Respirator Protection:
Respirators should be used only under any of the following circumstances:

As a last line of defense (i.e., after engineering and administrative controls have been exhausted).

When Permissible Exposure Limit (PEL) has exceeded or when there is a possibility that PEL will be exceeded.
 Regulations require the use of a respirator.
Piranha Solution 2 Date: 3/14/2014


An employer requires the use of a respirator.

There is potential for harmful exposure due to an atmospheric contaminant (in the absence of PEL)
 As PPE in the event of a chemical spill clean-up process
 Lab personnel intending to use/wear a respirator mask must be trained and fit-tested. This is a regulatory requirement. Contact EH&S 8-8411 regarding respirator clearance.
Hand Protection:
Handle with gloves. Regular Nitrile gloves do not provide sufficient protection. Heavy duty neoprene or rubber gloves must be worn.
NOTE: Consult with your preferred glove manufacturer to ensure that the gloves you plan on using are compatible with piranha solution.
Refer to glove selection chart from the links below: http://www.ansellpro.com/download/Ansell_8thEditionChemicalResistanceGuide.pdf
OR http://www.showabestglove.com/site/default.aspx
OR http://www.mapaglove.com/
Eye Protection:
ANSI approved properly fitting safety goggles are required, as well as a face shield.
Skin and Body Protection:
Lab coat, full-length pants, and closed-toe shoes are required. An acid-resistant apron is highly recommended.
Hygiene Measures:
Avoid contact with skin, eyes, and clothing. Wash hands before breaks and immediately after handling the product.
Use of piranha solution should be conducted in a properly functioning chemical fume hood whenever possible. The chemical fume hood must be approved and certified by EH&S and have a face velocity between 85 – 125 feet per minute.
If inhaled:
Move into the fresh air immediately. Consult a physician. If not breathing give artificial respiration and seek immediate medical attention.
In case of skin contact:
Immediately flush skin with plenty of water for at least 15 minutes while removing contaminated clothing and shoes. Wash any contaminated clothing before reuse. Thoroughly clean shoes before reuse. Consult a physician.
Piranha Solution 3 Date: 3/14/2014

In case of eye contact:
Check for and remove any contact lenses. Rinse thoroughly with plenty of water for at least 15 minutes and consult a physician. Seek immediate medical attention.
If swallowed:
Do NOT induce vomiting unless directed by medical personnel. Never give anything by mouth to an unconscious person. Seek immediate medical attention.

Before using Piranha solution, more stable methods of removing stains, tars, or clogs should be attempted.
Often, glassware can be cleaned if left with a cleaning solution. An immediate example for a suitable substitute, prior to using Piranha, is 98% Sulfuric acid.

Always use glass (preferably Pyrex) containers. Piranha will melt plastics.

Piranha solution should be used freshly-prepared, due to the self-decomposition of hydrogen peroxide. Do not maintain a stock solution of the Piranha mixture.
 Prepare small amounts of solution to be used for each application. Mix the solution in a fume hood with the sash between you and the solution. The solution may be mixed before application or directly applied to the material, applying the Sulfuric acid first, followed by the peroxide.

When preparing the piranha solution, always add the peroxide to the acid. Hydrogen peroxide concentrations should be kept below 30%, and should never exceed 50%.

Piranha solution should never be left unattended if hot.

Once finished, allow the hot piranha solution to cool in an open container. Once cooled down, put the waste solution in a container with a vented cap. Examples of vented caps are shown in Figure 1 on the right. Submit the waste solution as soon as possible to EH&S on a Hazardous Materials Pickup Request from.
 Never seal containers containing Piranha solution. Avoid using airtight containers as pressure can build up inside of them. Never store piranha solutions. Oxygen given off during the self-decomposition, as well as the oxidation products of organic compounds can cause the container to rupture.

Adding any acids or bases to piranha or spraying it with water will accelerate the reaction.

Mixing hot piranha with organic compounds may cause an explosion.
This includes acetone, photoresist, isopropyl alcohol (other organic solvents), and nylon. Figure 1: Example of vented caps.

Do not stockpile or accumulate Piranha solution. Submit to EH&S for chemical waste pick-up as soon as possible.
Piranha Solution 4 Date: 3/14/2014

Chemical Spill Dial 8-1911
Immediately evacuate area and ensure others are aware of the spill. If there is an imminent threat of a fire, pull the nearest fire alarm station to evacuate the building and dial 8-1911 . If the spill is minor and does not pose a threat to personnel, contact EH&S at 8-8411 during normal business hours (7:30 AM – 4:30 PM) for spill cleanup assistance (dial 8-1911 if spill occurs after hours and assistance is needed).
Chemical Spill on Body or Clothes:
Remove clothing and begin first aid procedures (Section 7) immediately. Seek medical attention; dial 8-1911 .
Chemical Splash into Eyes:
Immediately rinse eyes and begin first aid procedures (Section 7) immediately. Seek medical attention; dial 8-
1911.
Life Threatening Emergency, After Hours, Weekends And Holidays:
Dial 8-1911 .
Non-Life Threatening Emergency:
Immediately report injury to supervisor and complete the First Report of Injury. http://www.marquette.edu/riskunit/riskmanagement/documents/Employee_First_Report_of_Incident.pdf
Label Waste:
Make sure the waste container(s) is properly labeled; label should indicate all of the contents of the container.
EH&S provides hazardous waste labels free of charge, contact dennis.daye@marquette.edu
to obtain labels.
Store Waste:
Submit Piranha solution for waste pick-up as soon as possible. The Piranha solution must be cooled and kept in a waste container with a vented cap, and in a designated area.
Dispose of Waste:
Complete a Chemical Waste Pickup Request Form to arrange for disposal by EH&S. Contact dennis.daye@marquette.edu
or visit the EH&S webpage for questions. http://www.marquette.edu/riskunit/environmental/documents/waste_disposal_form.pdf
A current copy of the Piranha solution components’ SDS must be made available to all personnel working in the laboratory at all times. To obtain a copy of the SDS, refer to Marquette’s MSDS library http://www.marquette.edu/riskunit/environmental/documents/msds_library.pdf
or contact the chemical manufacturer. Many manufacturers’ SDSs can be found online on websites such as Sigma-Aldrich
( http://www.sigmaaldrich.com/united-states.html
) or Siri MSDS Index ( http://hazard.com/msds/ ).
Piranha Solution 5 Date: 3/14/2014

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NOTE: Any deviation from this SOP requires approval from PI.
(signature of all users is required)

Prior to conducting any work with P iranha solution , designated personnel must provide training to his/her laboratory personnel specific to the hazards involved in working with this substance, work area decontamination, and emergency procedures.

The Principal Investigator must provide his/her laboratory personnel with a copy of this SOP and a copy of the
SDS provided by the manufacturer.
 The Principal Investigator must ensure that his/her laboratory personnel have attended appropriate laboratory safety training or refresher training within the last one year.
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Piranha Solution 6 Date: 3/14/2014

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Piranha Solution 7 Date: 3/14/2014