The Chamber

A view of Big Fisherman Cove and the USC Santa Catalina Marine Biological Laboratory (SCMBL, now called the USC Philip K. Wrigley Marine Science Center) in the 1960s.
View a presentation by Dr. Andrew Pilmanis on the early days of the Lab and the Chamber program at:

In the late 1960s, the University of Southern California established the USC Santa Catalina Marine Biological Laboratory (SCMBL, now called the USC Philip K. Wrigley Marine Science Center) in the valley off of Big Fisherman Cove on Catalina Island. Shortly after the construction of the lab, North American Rockwell and the US Navy utilized it as a base for their testing of the submersible Beaver IV. The hanger they built to house and service the submersible would later become the home of the USC Catalina Hyperbaric Chamber.

Submersible Beaver IVThe focus of the USC SCMBL was research in the ocean environment. Since scuba was a primary research tool, studies of diving and decompression physiology found a natural home at the lab. In 1973, during an open ocean diving physiology study, one of the test subjects developed decompression sickness. At that time, the only hyperbaric chambers in Southern California were commercial and military chambers. Fortunately for the bent diver, Howard Hughes’s Glomar Explorer was performing sea trials around Catalina Island, and the diving barge supporting the Explorer had a hyperbaric chamber. Arrangements were made and the diver was treated.

Crane installing the Hyperbaric Chamber.This accident highlighted the need to have a hyperbaric chamber at SCMBL to support its divers. Dr. Andrew (Andy) Pilmanis, an assistant professor of physiology who was stationed at the SCMBL, and Dr. John P. “Pat” Meehan Jr. (Chairman of the Physiology Dept at the USC School of Medicine) began the search for a chamber to meet the needs of the lab.  Dr. Meehan called Dr. Charles Barrons, flight surgeon for Lockheed’s Skunk Works Rye Canyon facility to see if they would be interested in donating the chamber to USC (coincidentally, Lockheed’s Skunk Works were involved with development of the Glomar Explorer). The Chamber had been used to support test pilots (in case they developed altitude decompression sickness) during trials of their SST and SR-71 prototypes. Since these projects were complete, Lockheed agreed to donate the Chamber to USC. Bechtel Corporation donated the time and people to move it to San Pedro, Western Offshore Drilling Corporation (a subsidiary of Fluor Corporation) made some modifications to it, and then Pacific Tow & Salvage donated tug, crane, and barge services to transport it to CMSC. The Chamber was lifted from the barge and lowered onto the submersible marine railway. It was then winched up the railway into the hanger and then maneuvered, by hand, into the location it occupies today. Funding for the installation of the Chamber in its new home was provided by the USC Oceanographic Associates.

Dr. Pilmanis was appointed the first director of the Chamber. He, along with soon to be Dr. Bruce Bassett (an Air Force officer working on his Ph.D. at the lab who had set up the USAF hyperbaric chamber training procedures), worked on the installation of the Chamber. Using procedures adapted from the USAF they trained of the first Crew of the Chamber from members of the SCMBL staff and LA County Lifeguards stationed on Catalina. The Chamber’s first recorded occupied dive in its new home was made on July 13, 1974.

Originally, the Chamber was to be used for hyperbaric research and to support SCMBL’s research divers. However, it soon became clear that other divers needed support as well. In the early 1970s there were years where there were over 20 diving fatalities around Catalina Island and Los Angeles County. These fatalities illustrated the need for rapid response to diving accidents. As a result, Los Angeles County Supervisor James A. Hayes of Long Beach proposed and arrangement between USC and LA County where the County agreed to provide funding for operation of the Chamber 24 hours a day, 365 days a year, as well as medical support and direction for the treatment of divers from LA County Medical Center. With the assistance of Dr. Bassett and Dr. Jefferson Davis from the USAF Hyperbaric Center at Brooks Airforce Base, Dr. Richard Scott from the LAC+USC Department of Emergency Medicine trained physicians in hyperbaric medicine. These physicians would be transported to the island by the LA County Sheriff department. During the same time period the Los Angeles County (“Baywatch”) Lifeguards stationed in Avalon and Two Harbors received training to bring them up from EMTs to Paramedics to improved the emergency medical care of divers being transported to the Chamber and others who needed care on the island. The Chamber was formally dedicated in early October 1974 and did not need to wait long for its first patient, a recreational diver, who arrived for treatment on October 14. When it opened, the USC Catalina Hyperbaric Chamber was the only non-military/non-commercial diving chamber in the Southern California area and patients were brought in from as far south as Baja and North to Montery (Newspaper articles on the dedication of the Chamber). As it approaches 40 years of operation, the Chamber has received over 1,000 for evaluation. Of these over 600 required treatment. Since some required multiple treatments these 600+ divers have received over 900 treatments.

Over the years information from the diving accidents treated at the Chamber have led to recommendations for the entire recreational diving community. In the 1970s and 1980s, it was noted that many cases of air embolism treated at the Chamber were caused by free-ascent training in basic classes. Recommendations were made to modify free-ascent training and occurrences of these cases were reduced. A recent review of causes of panic in divers treated at the Chamber has produced recommendations on how to reduce a diver’s potential for panic. Based upon the cases of two unconscious divers who were brought to the Chamber, recommendations were made to scuba training agencies to prohibit instructors from using closed or semiclosed circuit rebreathers while training basic open circuit scuba divers.

Over the years, the Chamber has been used for hyperbaric and decompression research. For one study Dr. Pilmanis performed Doppler monitoring on divers who dove to the U.S. Navy no-decompression limits with and without un-required stops at 10 and 20 feet. He noted that the amount of bubbling dropped dramatically when short (2-5 minute) stops were made at 10 and 20 feet. This data, when presented at the American Academy of Underwater Sciences “Biomechanics of Safe Ascents Workshop” led to recommendations that have evolved into the 15-foot safety stop that every diver now knows. In 1983 the Chamber was used by Orca Industries to perform human subject tests on one of the first commercially viable dive computers, the EDGE. Karl Huggins, Orca’s Vice President for Research, used Doppler to monitor 12 divers through three days of three multi-level dives per day and a decompression dive on the last day in order to test for hot spots in the EDGE’s decompression algorithm. Nine years later Huggins was hired to become the Director of the Chamber. Ongoing work with dive computers, which compares their responses to set profiles, shows that on the same dive some computers may have over 10 minutes of decompression required while other have over 20 minutes of no-decompression time remaining.

No history of the Chamber would be complete without mentioning the Volunteer Crew, who are essential in making the system work. The original 1974 crew consisted of people who worked at SCMBL and lived in the Two Harbors area. In 1980, Dr. Pilmanis started a training program for anyone interested in volunteering. Since then, over 400 people from around the world have been trained. Currently, about 80 active volunteers donate their time. Without them, it simply would not be possible to operate the Chamber without dramatically increasing the budget. So the next time you meet some of these exceptional individuals, be sure to thank them for their service to the diving community.

Memorials to Chamber Founders

Learn about the founders of the Catalina Hyperbaric Chamber.

Bruce E. Bassett, Ph.D. (1936-2002)

Reflections from Andy Pilmanis, Ph.D (USC Catalina Hyperbaric Chamber Founder):


I took my hyperbaric chamber operations training from Bruce and Dr. Jeff Davis here at Brooks AFB in 1970. About 2 years later, Bruce became my graduate student at USC. At the time, I had several graduate students interested in diving physiology research and we were doing bubble detection studies in open water diving funded by the Office of Naval Research. We had DCS in one of our subjects and had to treat him in a small chamber that was in the area with the Glomar Explorer operations. This was the CIA/Navy “Jennifer Project” to raise a Russian Submarine and was a very classified operation being tested in the Isthmus area. As a result, the treatment of our subject was a very difficult experience. It was because of this incident and my desire to expand our diving physiology research that I was able to obtain the chamber.

When the chamber arrived in 1974, Bruce was in residence at Catalina to do him Ph.D. Dissertation research. He was heavily involved in the day-to-day set-up of the chamber. He had set up the USAF hyperbaric chamber training procedures and was invaluable in adapting those military procedures to our civilian operation. He was there in full uniform when the chamber was dedicated and opened in October of 1974. Ironically, our first patient was an active duty AF Major, also, unfortunately our first fatality (heart attack while diving, not a diving problem). I learned a great deal from Bruce during those ealy days, and we had some very interesting times “developing” new approaches to decompression procedures and treatment procedures.

Much of what… [is done at the Chamber now] now can be traced back to Bruce. He did his Ph.D. research in the chamber using trained dogs to determine the effect of exercise while at depth on DCS risk. He completed his Ph.D. and returned to Brooks AFB. His involvement did not stop there. During the 1970s, we used him (as well as Dr. Davis) for consultations on almost every case. He and Jeff Davis also came out periodically to train our USC doctors in hyperbaric medicine. During the 1980s, Bruce was also on the Advisory Board for the NOAA/USC National Undersea Research Program at the Catalina Marine Science Center in the development and construction of the underwater habitat “Aquarious”, currently operating off Key Largo.


Dr. Bruce E. Bassett, Aerospace and Diving Medicine Pioneer:


Bruce E. Bassett, Ph.D., Lt. Col. (Ret.) USAF, BSC, a pioneer in aerospace physiology and international diving medicine, died May 4 following a courageous battle with cancer. He was 66 years old. Dr. Bassett entered the United States Air Force after his graduation from San Jose State University in 1957, and spent many of his 23-year Air Force career stationed at Brooks AFB. He was highly regarded as a superior instructor in aerospace and hyperbaric medicine, and was instrumental in the establishment of the Hyperbaric Medicine Division of the USAF School of Aerospace Medicine. After completing the US Navy Diving Medicine training, he applied this expertise to the development of a worldwide system of USAF hyperbaric chambers. These chambers have been used since their completion for the treatment of aviators with decompression sickness (“bends”) and other clinical conditions.

In 1966, then-Major Bassett was called to Washington, and after undergoing higher-than-top-secret clearance at CIA Headquarters in Langley, Virginia, he was assigned as Chief of Life Support at Groom Lake (also referred to as Area 51) for the highly classified U-2 and SR-71 (Blackbird) spy-plane projects. There, in what he referred to as the pinnacle of his career, he helped design the pilot ejection and life support systems for the U-2 and SR-71. The unique pressure suit that he developed is now on exhibit in the Smithsonian National Air and Space Museum in Washington DC.

Upon completion of his Ph.D. in Physiology from the University of Southern California, Dr. Bassett returned to Brooks AFB, where he continued his research in the treatment of decompression sickness, including project studies on the differing effects on men and women of altitude decompression sickness, and the first manned studies of the effects of flying-after-diving on the risk of developing the “bends.” Dr. Bassett also trained many groups outside the USAF in diving medicine. He was on the advisory board for the USC/NOAA National Undersea Research Program, which developed the nation’s only underwater habitat in current use.

After retiring from the air force, Dr. Bassett and his wife, Anita, founded Human Underwater Biology Inc, as providers of international Continuing Medical Education for medical professionals. Their fully accredited CME programs offers a diverse range of topics, including varying aspects of Diving Medicine, Environmental Medicine, Solutions for Dealing with Difficult Patients, Emergency Medicine, Hot Topics for Primary Care Physicians, Updates in Infectious Disease, and Addiction Medicine. Dr. Bassett was a Fellow in the Aerospace Medical Association, Past President of the Aerospace Physiology Society, past Executive Member of the Undersea and Hyperbaric Medical Society, member, Texas Association of Alcohol and Drug Abuse Counselors, and a member of the International Society of Travel Medicine. His achievements include the Wiley Post Award for Operational Aerospace Physiology, the Paul Bert Diving Award of the Undersea and Hyperbaric Medical Society, and numerous USAF Commendation and Meritorious Service Medals, in addition to the Outstanding Instructor Award at the USAF School of Aerospace Medicine. He is survived by his beloved wife, Anita; and four sons, Hollis Edwards of Dallas TX, Greg Bassett of Basking Ridge NJ, Steven Bassett of Brooklyn NY, Andrew Bassett of Flemington NJ, his brother Jerry Bassett M.D. of Coquille OR, one grandchild and numerous extended family members and friends. Dr. Bassett will long be remembered for his many professional contributions, and as a loving husband and father, a wise and unselfish mentor, and a valued friend to the many people — local, national, and international – whose lives he touched.

Dr. John P. Meehan Jr. (1923-2002)

Reflections from Andy Pilmanis, Ph.D (USC Catalina Hyperbaric Chamber Founder):


Dr. “Pat” Meehan was my mentor, my major professor for my Ph.D., and friend. I was one of the 14 subjects for the Bedrest experiment in 1964 mentioned in the article (below). Many other physiologists received their training under him including Bruce Bassett, Bret Stolp (currently at DAN), and a number of the military physiologists I previously and currently work with. After I received my Ph.D., I was on the faculty for 7 years in the Dept of Physiology, of which he was Chairman. He was a strong supporter of the Catalina Marine Science Center (as it was called then) from the beginning.

In 1973, I was doing ONR funded open ocean diving research and one of my subjects bent. We had to get him treated on a diving barge supporting the Glomar Explorer (THAT was an experience). At that point I decided we needed a chamber in support of the research for safety, but also for research I could not do in the ocean. I put out the word. Pat Meehan called Dr. Charles Barrons, flight sureon for Lockheed Rye Canyon facility and talked him into donating the chamber to USC. The USC Oceanographic Associates got Bechtel Corp. to donate the time and people to move it to San Pedro, and Pacific Tow and Salvage to donate one day of tug, crane and and barge to bring it over to the Lab. Union rules forbid the crew from coming ashore. They put it on the marine railway and left. Dr. Meehan brought over his engineer and technicians and together we placed the chamber and the compressor skid and installed the equipment.

As Chairman of the Physiology Dept at the USC School of Medicine, Dr. Meehan was also instrumental in convincing the County Hospital in supporting the chamber for treatment of diving accidents (the original purpose was research only). Dr. Richard Scott picked it up from there and developed the response system you now have. Meehan continued to support the chamber for a number of years in ways that were not high profile but absolutely critical for safe operation. He knew nothing about diving, but was an excellent physician, physiologist and engineer (Cal Tech).


John Meehan Jr.; Studied Weightlessness for NASA Space Flights:


John P. Meehan Jr., 79, retired USC professor of physiology who studied the effects of weightlessness and acceleration for NASA, died Oct. 23 in Los Angeles of leukemia.

Born in San Francisco and reared in San Marino, Meehan earned his bachelor’s degree from Caltech and his medical degree from USC. During the Korean War, he served as an Air Force colonel heading the Arctic Aeromedical Laboratory at Ladd Air Force Base in Fairbanks, Alaska.

As a physician, Meehan delivered two of his own children while stationed at the remote base. During World War II, he conducted research for the military leading to the development of pressure suits for fighter pilots at high altitudes. Meehan joined the USC faculty in 1947, and served as chairman of its physiology department from 1966 until his retirement in 1987.

He was associated with NASA for several decades, and with a centrifuge he helped design and construct the original astronauts’ space suits. A master machinist, he also designed and built their monitoring devices, which continually apprised mission control of their heart rates and blood pressure.

In one of his studies to determine problems with weightlessness in 1964, called Operation Sacktime, he put 14 USC students in bed for 30 days and devised exercises for them to prevent dizziness on rising. The experiment simulated astronauts’ anti-gravity suspension status during space flight.

In the 1970s, Meehan helped Los Angeles County acquire a hyperbaric chamber to treat divers suffering air embolisms or decompression sickness known as the bends. USC operates the chamber at the Marine Science Center on Catalina Island.

USC Catalina Hyperbaric Chamber

P.O. Box 5069
1 Big Fisherman Cove
Avalon, CA 90704

Emergency Numbers

Catalina Chamber 24 Hour Emergency Line
(310) 510-1053

LA County Medical Alert Center (MAC)
(866) 940-4401

U.S. Coast Guard Sector LA/Long Beach Search & Rescue
(310) 521-3815
Marine Channel 16

Divers Alert Network (DAN) Emergency Line
(919) 684-9111