Steve Ringhoff is a retired attorney and investigative journalist who formerly wrote for the Modesto Bee. His recent investigation (see link below) into the deaths of Jason Garner and Raschel Johnson is a classic of investigative reporting. Read more of Steve’s fine work here. 

Understand: There is no real “canary” for carbon monoxide poisoning. You may get a headache, or not; be fatigued, or not, be nauseated, or not. You can be poisoned without realizing it. And, long term exposure to low levels of carbon monoxide levels may cause behavioral changes such as aggression, depression and other symptoms similar to PTSD.

Sometimes the first to recognize the change is a family member.

We began this follow up to our series on the Garner/Johnson crash concerned that the systems of monitoring used by the Modesto Police Department and the Stanislaus County Sheriff’s Office may not detect leaks from the exhaust system at levels low enough to protect their officers.

Then we realized that this inquiry really begs the question, which is: Why should we have to be monitoring for exhaust leaks, worried that the users might suffer long term effects of carbon monoxide poisoning even after their shift ends, and for their future?

Ford has denied there are any inherent problems with the design of their exhaust system; has offered band aid fixes; has blamed agencies for the holes they made installing police equipment and has refused to recall the Police Interceptor Utility vehicles which it only sells to law enforcement.

For those of you who do not savor details, here are bullet points about the issues raised in this article:

 –Exhaust manifolds in Ford Police Interceptors and Ford Explorers in police use are prone to cracking, warping and leaking.—This can lead to the accumulation of carbon monoxide rich fumes in the engine compartment.

–These leaks arise unpredictably and are not always detectable in routine maintenance procedures.

–These fumes can be drawn into the passenger compartment under certain “climate control” settings through “fresh air” ducting.

–Carbon dioxide detectors currently in use are not designed to alert the operator to some sub-lethal exposures.

–Repeated exposure to sub-lethal levels can lead to physical, mental and behavioral changes that persist even after daily exposure stops.

Our recent three-part series examined the investigation of the May, 2017, crash which took the lives of two employees of the Stanislaus County Sheriff’s office, Deputy Jason Garner and Community Service Officer Raschel Johnson. Blood tests in that case pointed to ACUTE (immediate) exposure to high levels of exhaust gases. This may have caused the erratic driving–speeding at nearly 90 mph–ending in a wrecking yard on the wrong side of the road for that 2014 Ford Interceptor Police Utility vehicle.

We focus not only on the causes of the exhaust leaks but also on the short and long term symptoms caused by lower level exposure to exhaust fumes. Some doctors call this chronic because the symptoms persist even after the exposure stops.

We are prompted to examine this chronic exposure after reviewing a mechanical inspection of one of these vehicles prepared as part of an investigation by the Washington State Department of Labor and Industries. This resulted in a flyer sent by that agency last month to every law enforcement agency in Washington detailing the findings and suggesting proper monitoring of the vehicles.

This report disclosed inherent defects in these vehicles including a path of entry of exhaust gas into the passenger compartment not previously reported. This represents an exposure scenario different than Ford has previously suggested.

Ford blamed exhaust fumes in the passenger compartment on the law enforcement agencies. Ford said the agencies left what its spokeswoman said were “huge gaps” in body panels when they installed lights, sirens and other things unique to each agency. Ford also suggested minor leaks around the back hatch and other places might contribute to exhaust fume smells.

Both scenarios, however, were focused at the rear of the vehicle. This new scenario is forward of the passenger compartment.

The Washington report says accumulated exhaust fumes come into the vehicle through the heating and air conditioning ducting in the grill or cowling after the exhaust manifolds crack or become warped or certain joints in the exhaust system pipes are damaged.

Ford has denied there are inherent problems with the design of the Interceptor or the Explorer and has refused to voluntarily recall the vehicles. Ford does have “customer satisfaction programs” which allow repairs by dealers at low or no cost, if the owner complains.

The National Highway Safety Administration (NHTSA) has opened an investigation but has reached no conclusion and made no recall orders. This investigation has resulted from nearly 2,000 complaints and from several incidents involving law enforcement.

In a written response to our recent inquiry, NHTSA said it would not comment until the investigation is complete and a course of action decided upon. Some auto safety advocacy groups have asked for a recall of all 1.3 million Explorers.

The Washington reports points to a defect in the design of the exhaust manifold. Leaks in the manifold fill the under-hood compartment with exhaust fumes. Because these fumes can leak out before they reach the catalytic converter, the fumes are carbon monoxide rich.

The Washington report notes the misdirection caused by Ford’s claim that the problems were at the rear of the vehicle and caused by “seams in the body, small holes, body plugs, police equipment installations and vents.”

The report says that if this was the problem, it would have existed from the first day of service and throughout the life of the vehicle. Instead, the problem does not show itself until midlife of the vehicles, according to the report. About 10 percent of the more than 600 Washington Patrol vehicles registered carbon monoxide in the passenger compartment after all of Ford’s repairs or modifications had been completed.

It goes on to note that exhaust manifold leaks occur after a time and after repeated expansion and contraction of the manifold, saying:

“The continual expansion and contraction of the manifolds takes its toll. The design of the manifold is not cast in a single piece but consists of a thick mounting flange (.32”), the thin stamped sheet metal runners (15 gauge .067” thick) and the catalytic converter in one compact unit. The continual expansion and contraction of these conjoined components, each a different thickness and with different cooling and heating rates, over a period of time seem to stress the metal to the point of failure, The placement of the catalytic converter, just a few inches from the cylinder head, along with the short, stamped sheet metal exhaust runners is an area of great stress, high pressure and high temperatures.”

In addition, the report notes the contraction and expansion can cause leaks at the manifold gasket, the connection to the engine’s cylinder head.

Compounding the problem, the report notes, is the fact that the manifold cracks are not always noted by a diagnostic trouble code when a mechanic reviews computer readouts of potential problems.

The report explains that fresh air is drawn into the passenger compartment climate system through a plenum with an opening just behind the hood, in front of the driver. It is also drawn in through an opening near the grille.

“If there are any voids, holes or open seams in these panels, or leakage in between these panels where they come together, the vacuum of the HVAC fan will pull that (engine compartment) air in. And that is exactly what is happening,” according to the report.

So, how to protect users of these vehicles during the time period between the start of the leakage and its discovery?

The Washington state agency suggests using a monitor which:

1. Provides and stores continuous and peak carbon monoxide measurements.
2. Can be set to vibrate, sound or flash when CO concentrations reach occupational exposure limits.
3. Has a built in calibration feature to ensure continued accurate measurement.
4. Can handle rough conditions during use.

The monitoring device currently in use by the Modesto Police Department (MPD) has none of those features. The primary monitoring tool, according to MPD Spokesperson Sharon Bear is a colored “button” device which adheres to the interior and changes color when a certain level of exposure is reached.

(Two separate officers have told us that one crusty old cop used a piece of chewing gum to stick the button on the end of his baton. He then put the end of the baton into an exhaust pipe of a running vehicle. It didn’t change color, according to that anecdote.)

The secondary device is the officer. If fumes are detected by the officer’s senses, a supervisor is called and can check the vehicle with a more sophisticated device.

There are a number of problems with this system. First, the button device, according to its manufacturer’s specifications, will not alert to exposure until it reaches 100 parts per million (ppm). The World Health Organization (WHO) suggests that an individual not be exposed to enough carbon monoxide in the work day to reach an average level of 2.5 per cent in the blood which is stated as a percent in the hemoglobin.(carboxyhemoglobin).

“Psychomotor effects such as reduced coordination, tracking and driving ability, and impaired vigilance and detection of small environmental changes have been revealed in double-blind studies at COHb levels as low as 5.1-8.2%”, According to the WHO.

Nausea and headaches are “classic” symptoms of carbon monoxide poisoning but are not always the first. There are published “standards” about carbon monoxide poisoning but they are general related to acute rather than chronic exposure.

Recent medical literature raises doubt about the safety of all carbon monoxide exposure “standards”, according to Albert Donnay, MS, MHS, of Maryland.

Historically, the ambient air had about 9 ppm and standards, for example, of 35 ppm were considered safe then. Thanks, in large part to the EPA, the current ambient air is at about 3 ppm. As a result, the population is habituated to that level. So the old standard had the “safe” standard at about four times the ambient level. The “safe” standard is now about 11 times the ambient level.

Ford has said that any leaks do not expose occupants to carbon monoxide above the recognized workplace standards which as 35 ppm.

That level is the setting for the devices used by the sheriff’s office. But at slightly less than 35 ppm, you can get to the 2.5% blood level in an hour, according to the WHO. And, the sheriff’s device does not store readings, including peaks. The SO uses a Sensorx device which actually measures and displays exposures but does not store them.

So a leak producing 90 ppm would not cause the MPD’s “button” to note the gas, and a leak producing 30 ppm in a sheriff’s car would not cause the alarm to sound… all day, every day.

It takes 15 minutes to get to 2.5% at 90 ppm and about an hour at 30 ppm.

The long term effects of relatively low level poisoning are not fully understood but do linger after the exposure, evidence of which includes anecdotal stories about Washington state trooper’s wives not letting their husbands drive the family car after they had worked a shift because the wife perceived impairment.

A number of troopers have filed suit against the State of Washington claiming disabling injuries, some of them akin to PTSD.

Beyond the “button” device” issue, an exhaust manifold which is fine one day begins cracking and warping then leaking. From that point until detection and repair, the occupants are potentially exposed to carbon monoxide.

Calling out a supervisor with a more sophisticated detection device may not work because even with a manifold leak, the climate control setting and use of the vehicle may not cause fumes in the passenger compartment.

The manifolds in Ford SUVs for police use are more susceptible to leakage because the cars are subject to periods of high acceleration with the attendant expansion, followed by contraction when the vehicle is slowed down

Detection during routine inspection does not necessarily come easily. Visual inspections are difficult because of the positions of the manifolds. Trouble codes are not necessarily activated. So, the first sign might be when a detector alarms at the set level, after a period of exposure to the occupants. Replacement of the manifold with an identical manifold does not solve the problem.

The Washington state report says that leaks come in mid-life of the units. The Sheriff’s Interceptor in the Garner/Johnson unit was replaced at about 54,000 miles. That vehicle had about 85,000 miles of use when it crashed.

Simply put, a vehicle inspected and cleared one day may leak badly the next.

We provided the Modesto Police Department with a copy of the mechanical inspection from the Washington state entity and information about the WHO recommendations. The city’s public relations officer says the city is happy with the monitoring system it has and has detected no problems, themselves or through inspections from independent examiners.

Agencies have a big investment in these vehicles. They cost more than $30,000 each before the specialized equipment is installed. So the city’s 35 or so vehicles represent an investment of over $1,000,000.

(The Explorer and Interceptor are two distinct vehicles but share many parts beyond the shell, including the exhaust system. An Explorer which is in daily in police use may be subject to the same acceleration/deceleration and contraction/ expansion stresses as the Interceptor. The Interceptor is a high horsepower pursuit rated vehicle).

TAKEAWAY: The agencies may be between the proverbial rock and the hard place. What to do? How about not accepting the risk? How about saying to Ford:  put out a manifold not prone to leak, or take the car back?