On 1 November 2020,PADIOpen Water DiverLinnea Rose Mills^[1] drowned during atraining dive inLake McDonald inGlacier National Park, Montana, while using an unfamiliar and defectiveequipment configuration, with excessiveweights, no functionaldry suit inflation mechanism, and abuoyancy compensator too small to support the weights, which were not configured to beditched in an emergency.^[2][3] She had not been trained or given a basic orientation in the use of a dry suit. This defective equipment configuration was supplied by the dive school, and the instructor, who was registered but had not been assessed as competent to train dry suit diving, did not take appropriate action compliant with PADI training standards or general recreational diving best practice, at several stages of the dive.^[3] Several levels of safety checks which should have detected the problems failed to do so.^[4]

During the dive, her dry suit was compressed by the ambient pressure, and as she was unable to add gas to restore buoyancy, she becamenegatively buoyant and was unable to swim upwards, further hindered bysuit squeeze. She fell off an underwater ledge while trying to attract the attention of the instructor, and though a fellow diver attempted to stop her descent, he was unable to ditch any of her weights and had to surface to save himself.

The incident was poorly investigated and as of November 2024, no criminal charges have been made, but a civil case for $12 million was eventually settled out of court, and counsel for the plaintiffs has urged the state to prosecute. TheProfessional Association of Diving Instructors was alleged to have failed in theirduty of care by not providing sufficient quality assurance oversight on the dive school and instructor, and by setting standards for training that were ambiguous and in places contradictory, relying on interpretation by the service provider, which allowed plausible deniability of responsibility by PADI if an accident occurred.^[3]

The Missoula dive shop Gull Dive, owned by David and Jeannine Olson, was advertised as a PADI dive school. It rented equipment to Mills, and employed the dive instructor responsible for the training.^[3]

The dive site,Lake McDonald is a coldfreshwater environment,^[5] and adry suit would be standard equipment for the expected conditions. Lake McDonald is the largest lake inGlacier National Park. It is located at48°35′N113°55′W / 48.583°N 113.917°W /48.583; -113.917 inFlathead County in theU.S. state ofMontana. Lake McDonald is approximately 10 miles (16 km) long, over a mile (1.6 km) wide, and 472 feet (144 m) deep, filling a valley formed by a combination of erosion andglacial activity, with steep sides and a relatively flat bottom, requiring good buoyancy control to avoid sinking to excessive depths if overweighted.^[6] The surface area of the lake is 6,823 acres (27.61 km²). Lake McDonald lies at an elevation of 3,153 feet (961 m)^[7] and is on the west side of theContinental Divide.^[8]Atmospheric pressure at this altitude is approximately 89% of sea level, and this causes gas volume reduction at depth due to hydrostatic pressure to be greater than at sea level, which exacerbates the effects of suit squeeze.Altitude decompression is also affected by the lower surface pressure, anddecompression schedules andalgorithms must be adjusted to control the risk ofdecompression sickness. These problems are generally not familiar to divers who have not been trained inaltitude diving.

Thediver certification agency,PADI, is the largest recreational diver training agency in the world, and has considerable influence over international minimum training standards by virtue of their overwhelming worldwide market share. PADI training is focused on short, convenient courses, marketed by an emphasis on "fun" and claiming high standards of safety. As of 2020, PADI claims to have issued 28 million scuba certifications of all levels, many of which may be minor specializations. Some of the certifications align withWRSTC and ISO minimum standards, and these are recognized worldwide. Many of the others are not relevant for recognition, as they are unique to PADI and have no equivalence anywhere, or may be part of other agencies' standards for certification for more general diving skill levels, or are not universally accepted as necessary for diver competence or safety. PADI advertises itself as having a strong quality assurance system for members, which include PADI Instructors, PADI Divemasters, and PADI Dive schools, which are contractually obliged to adhere to PADI's standards and pay a significant annual membership fee for the privilege of using the highly recognized PADI name and logo, and for selling PADI training materials and certification. As the training agency, PADI is responsible for ensuring that all certification issued under terms of recognition by international standards agencies, complies with the relevant international standards. PADI is owned by Canadian investment firmAltas Partners and French private equity firmFlorac.^[9]

The instructor, Debbie Snow, a newly certified^[a]PADI Open Water Scuba Instructor,^[b] was initially trained as an instructor inFlorida in warm sea water but did not pass the evaluation on her first attempt. Two months later she was reevaluated and registered as an instructor with PADI. At this time she was also registered as an instructor for five specialty courses, including Dry Suit Diver by Rainbow Reef, the school she was trained at as an Open Water Instructor,^[10][11] Dry suit diving andaltitude diving expose the diver to a set of hazards not generally encountered in entry-level diving as covered by the Open Water Diver course.^[12] Such levels of training are generally considered to require specialization training for recreational divers to allow the diver to dive safely and make an informed acceptance of risk. Snow's familiarity with the dive site is unknown.^{[citation needed]}

Snow was assisted by another employee at Gull Dive, Seth Linton (22), whose only diving certification wasJunior Open Water Diver,^[3] a certification issued to entry level divers between 10 and 14 years old, otherwise equivalent to PADI Open Water Diver. His further experience was not specified, but stated to be hardly greater than that of Mills.^[13][c]

The decedent, Linnea Mills (18), was certified as aPADI Open Water Diver, had a total experience of five dives in warm water and one dive in Lake Seeley, in cold water, in awetsuit, and had never dived in a dry suit before the incident.^[10] She was enrolled on a PADIAdvanced Open Water Diver course through Gull Dive, of Missoula.^[14][15]

Mills was wearing a second hand dry suit she had purchased from a private seller, facilitated by the dive school, because they could not rent a dry suit to a diver who had not been trained in the use of a dry suit. Mills had not used a dry suit before, but she was not given a theory class, a briefing or confined water orientation in dry suit diving before the dive, which would have allowed the selection of appropriate weights and identified any obvious defects or other problems. The dry suit had a relatively uncommonCEJN connector inflation fitting and thescuba diving regulator set rented from the school did not have a compatibledry suit inflation hose connected, so it was not possible to add gas to the suit to relievesuit squeeze, or compensate for buoyancy reduction due to suit gas compression at depth. Mills was wearing a small, jacket stylebuoyancy compensation device (BCD) with a nominal lift capacity of 29.2 pounds (13.2 kg), rented from the school, anddiving weights totaling 44 pounds (20 kg) distributed as 20 pounds (9.1 kg) in the zippered pockets of the dry suit and 24 pounds (11 kg) in the zippered pockets of the BCD, which could therefore not be easily jettisoned in an emergency, also supplied by the school. Thewatertight zipper of the suit was reported to not close completely and would therefore allow air to escape and water to leak in, and the suit was a poor fit with over-large boots and over-long trouser legs.^[6] At the start of the dive, Mills had positive buoyancy with her head out of the water at the surface with an inflated BCD and an unflooded dry suit with unknown buoyancy.^[d][2]

Mills had not filled in amedical statement on enrolling for the course, nor anywaiver, liability release, orassumption of risk. The dive school had rented equipment four months earlier to an uncertified diver who subsequently drowned while using it.^[10]

The group of divers from Gull Dive arrived at Lake MacDonald at about 4 p.m. as daylight was fading. Two additional students who had completed dry suit training were already waiting there. While preparing for the dive, the instructor's assistant discovered that the regulator's low pressure hose fitting was incompatible with Mills' dry suit, and notified the instructor, who told Mills to use the BCD for buoyancy control during the dive.^[15][3]Use of the BCD is standard practice for general buoyancy control, but the absence of an inflator hose makes it impossible to relievesuit squeeze and retain basic suit buoyancy.^[16][6]Mills was given 44 pounds (20 kg) of loose dive weights instead of the standard quick-releaseweight belt orintegrated weight pockets for the BCD, which were loaded into the dry suit (20 lb)^[e] and BCD zipper pockets (24 lb). None of the weights were visible or easily jettisoned in an emergency by Mills or by another diver.^[15] It is not known who put the weights in the suit's pockets.^[6]

No on-sitedive briefing was given, and Mills was not assigned adive buddy, which would normally imply that the instructor would personally monitor the student throughout the dive, and the group entered the water at about 5 p.m., a short time before sunset. They descended to about 15 feet (4.6 m) and after about 5 minutes, one diver was cold and needed to surface. The instructor escorted the cold diver out of the water,^{[clarification needed][15]} leaving Mills without professional supervision or a properly allocated buddy.^[f] After returning to the group, the instructor and assistant took Mills and Bob Gentry to 60 feet (18 m). Gentry was carrying anaction camera on a frame with two video lights, which recorded much of the activity of the dive.^[15][11]

At 60 feet (18 m), the dry suit was significantly compressed by the ambient pressure of 1.8 atm above surface atmospheric pressure of about 0.89 atm. The air in the suit was compressed to less than 1/3 of the volume at the surface, and suit buoyancy had decreased in proportion. Mills was standing on a ledge, unable to swim upward due to insufficient buoyancy, and was unable to attract Snow's attention when she swam past with her attention apparently fixed on thecompass in her hand. Mills then signaled to Gentry, the diver with the GoPro, who approached her to assist, but she fell backwards off the ledge and began sinking. Gentry eventually caught up with her at a depth of 85 feet (26 m), wheresuit squeeze would be making it relatively difficult for her to move.^[3]

Gentry attempted to find and release Mills' weights but could not find them, and tried to provide her with air from hissecondary demand valve when she dropped her demand valve.^[g] An effort by Gentry to lift Mills and swim her up by finning hard failed and Gentry left her as his own air was running low. He made a rapid ascent to the surface from 105 feet (32 m) in less than a minute, putting himself at a raised risk ofdecompression illness. When he reached the surface, he was alone, but Snow surfaced after an undisclosed period. Gentry informed Snow of the emergency and she dived to look for Mills, but failed to find her.^[h] On a second search dive, by Snow and Liston, Mills was found at 127 feet (39 m), a depth significantly greater than the 60 feet (18 m) limit set by PADI for Open Water Diver certification. Liston then made a rapid ascent to the surface and Mills was recovered to the surface by Snow, after ditching thescuba set with the weights in the BCD pockets.^[15][3]

Snow and Liston were airlifted to Seattle, Washington, "for treatment for potential injuries", since Liston had been complaining of effects of his rapid ascent and had used up the available emergency oxygen.^[15][3][i] Consequently, they were not on site when the initial investigators and coroner arrived.^[11]

Several other irregularities and alleged breaches of PADI procedure and general recreational diving safety procedure were cited in the complaint lodged for civil action, some of which may have had a material influence on the outcome of the dive. Others were more relevant to non-compliance with PADI standards by Gull Dive and Snow.^[3]

The initial investigation was conducted by local park agents who consulted a range of diving specialists, but it was soon taken over byNational Park Service Investigative Services Branch (ISB), who stopped consulting with diving accident experts, and did not even call in their owndiving safety officer,dive team ordiving control board, who would normally be involved in a diving fatality investigation.^[17]

There were a number of irregularities in the investigation that the investigators may not have noticed, possibly due to a lack of training and expert advice.^[17] This is not an isolated incident, as many diving accident investigations in the US have been poorly managed by investigators without the necessary competence.^[18][19] Allegedly the ISB did not consider thedive profiles of Snow and Mills as recorded by theirdive computers, which showed that Snow was at the surface while Mills was drowning. According to counsel (David G. Concannon),^[j] Snow had failed to hand over Mills’ dive computer and personal effects, including partially completed PADI forms, to investigators,^[17] and the investigators did not pursue this. According to Concannon, Mills' dive computer was on her wrist when her body was taken ashore but was removed before the medics arrived, "found its way" into Debbie Snow's truck, and was taken home with her. The initial investigator from Glacier Park tried to find the computer which he thought had been taken to the morgue. The second group of investigators went to Snow's home to interview her, and were shown the dive computer, told it was not downloadable, shown the display of the dive profile and got a photo of it, which they were unable to interpret. They left the computer with Snow, and it was then passed on to a lawyer who worked with PADI, who took it to California along with Snow's computer and Liston's computer. It stayed there for one and a half years. The head of scientific diving at Scripps university downloaded them as a consultant to the lawyer, but the data was never produced as evidence until the civil litigants got a court order. A commentator raised the question of why PADI, which claimed to consider diver safety a high priority, would not actively work towards making the data public, as it would be in the interests of diver safety to do so.^[11]

InUS Federal Law the owner of equipment that logs data during an incident that may be the subject of litigation is obliged to preserve that data and make it available as evidence if the case comes to court at a later date. Litigants are required to find out what they have and disclose everything relevant to the opposition.^[21]

The video of the incident was not taken into account by the federal investigators; non-divers reviewed PADI's training standards and only after the instructor had been interviewed.^[17]

Jeannine Olson, who had no first-hand knowledge of the events of the dive, allegedly told theFlathead County DeputyCoroner that Mills was "witnessed by a dive buddy topanic, then fall passively to the bottom of a lake after swimming without difficulty at a depth of approximately 40 feet", which is contradicted by the evidence of the video recordings serendipitously made during the dive, which cover the events extensively.^[11] As a result, the medical examiner did not document the bruising on Linnea's body caused by the dry suit squeeze or other complications arising from high pressure. Olson also allegedly contacted Gentry afterward, claiming he was responsible for Linnea's death.^[15]

This sectionneeds expansion with: allegations of incompetence of the investigators.[11] Failure of investigators to recover Mills' dive computer.[11] Failure of PADI to release Mills' dive computer to the investigators[11] Allegations of threats by/at DEMA[11] c minute 38, Lee Ann and Lamar Hires invited Lisa Mills to DEMA to hand out buddy tags and got harassed by DEMA authorities Allegations of attempted cover-up by PADI[11] Coroner's report did not mention some important evidence[11]. You can help byadding to it.(November 2024)

The plaintiffs in the civil suit have alleged several breaches of general recreational diving safety protocols and violations of PADI and general recreational diving and training standards.^[3] Some of the standards are not easily accessible for the general public, making it difficult for a diver with only an entry level certification to find out whether standards are being followed for a course they have not done. Consequently, students have little choice but to assume that the instructor is actually following the standards if they want to get the training.^[10] Because the recreational diver training industry in the US is officially self-regulating, violations of training standards are not inherently illegal, and members of the public are obliged to fall back on assumptions of duty of care, contractual obligations, and expectation of a service provider to conduct appropriate safety measures, as generally accepted within the industry and as specifically required by the terms of training standards and membership agreements, for protection against negligence. The diving public also has an expectation that a training and certification agency will ensure that their members comply with their standards and terms of membership by way of an effective quality assurance system.^[3] This situation is aggravated by the service provider requiring the client to sign waivers granting the service provider and certification agency indemnity for negligence to the greatest extent legally possible.^[20]

In theComplaint and Demand for Jury Trial to the Montana Fourth Judicial District Court Missoula County, Concannon alleged several violations of PADI training and dive leadership standards:^[3]

After Mills' death PADI continued to issue certification in Snow's name, including to divers who were present on the fatal dive, and had not completed the course requirements for the dive due to the incident.^[10]

The incident and subsequent civil lawsuit were reported with varying accuracy, detail, and neutrality or lack thereof, by a local television station,^[22][23] other local news sites.^[12][15] internet diving magazines and blogs.^{[17][24][5][2][10][13]}

There has been strong criticism of PADI's reactions and lack of reaction to this incident, including suggestions that PADI is more concerned with profit than diver safety.^[10][11][6]

The quality of the investigation by the federal investigators of National Park Service Investigative Services Branch has been severely criticized for being incomplete and poorly conducted, with findings that are based on misinformation from some of the witnesses and disregarding video footage that is impartial, unambiguous and fairly comprehensive, and leading to the state attorney not having sufficient evidence to prosecute a convincing criminal case. There is no statute of limitations on homicide, and when additional evidence and leads were provided to the investigators by counsel for the plaintiffs, it appears to have been disregarded, so that four years after the incident no apparent progress has been made.^[11][6][3]

This sectionneeds expansion. You can help byadding to it.(November 2024)

Several stages of safety precautions are expected to be in place to prevent such an incident from occurring. These are based on industry standards for recreational diver training, and were the combined responsibility of the recreational diver training industry body for the US,RSTC, the training agencyPADI, the proprietors of the dive shop/school, Gull Dive, and the instructor, Debbie Snow. Several organisational cultural factors have been identified which contributed to the situation in which the incident occurred.^[4]

This sectionneeds expansion with: analysis from[4] What are the expected safety measures, and why did they fail.. You can help byadding to it.(April 2025)

A wrongful death lawsuit was filed inMissoula County District Court by Mill’s parents and other dive trainees in May 2021 alleging that Gull Dive instructors were not sufficiently qualified and failed to follow several safety requirements stipulated byPADI training standards, and were negligent and failed to exercise reasonable care before, during and after the dive.^[3]

It was alleged that Snow failed to check the equipment Mills was to train in, or her competence to use it, and allowed Mills to use an inappropriate and dangerous combination of gear. It was further alleged that during the dive, Snow failed to sufficiently monitor Mills’ situation or to take corrective actions as the incident developed.^[12]

The suit was for $12 million for compensatory and punitive damages,^[14] against Gull Dive, owners David and Jeannine Olson, diving instructor Debbie Snow, and shop employee and volunteer dive assistant Seth Liston. The Professional Association of Diving Instructors Worldwide Corporation, (PADI) and its wholly owned subsidiary PADI Americas Inc. was accused of negligence in its oversight of member businesses, but denied vicarious responsibility on grounds that member shops and instructors are not agents of PADI, which is no more than a professional organization and certifying agency, with members who operate independently, so PADI is therefore not responsible for their actions or omissions.^[12]

PADI's argument that Gull Dive and their staff were neither its agents nor employees, and that it could not be held responsible for the death of a client of Gull Dive was overruled by a judge, who stated that PADI exerted control over Gull Dive and its instructors by way of its membership agreement, which obliged members to follow its standards and instructions.^[17]

A settlement for an undisclosed amount was reached in February 2023.^[14] Snow's membership of PADI was subsequently terminated on 19 January 2023,^[25] about the time of the settlement. Gull Dive was dissolved by the owners in 2022. The volunteer safety diver was originally cited but later dropped from the suit.^[17]

None of the defendants in the civil case were criminally charged after an initial investigation. The U.S. Attorney for the State of Montana declined to press criminal charges against Snow, claiming the state could not prove criminal culpability beyond reasonable doubt.^[12]

Counsel for the plaintiffs in the civil case, David G. Concannon, suggested that if the federal investigators took the trouble to follow the chain of custody for the dive computer worn by Mills, which was taken out of state for two years, instead of being handed over to the investigators, they could charge those responsible for suppressing the evidence.^[24]

This sectionneeds expansion with:[11]. You can help byadding to it.(November 2024)

This section is empty. You can help byadding to it.(November 2024)

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• November 2020 in the United States
• Sports deaths in Montana
• Underwater diving deaths

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