Henderson County Toxic Exposure and Industrial Injury Accountability: The Attorney 911 Guide to Mesothelioma, Benzene, and East Texas Workplace Safety

For decades, the men and women who clocked in at the Athens Brick Company, maintained the high-pressure steam lines at the Trinidad power plant, or serviced the deep rigs of the East Texas Oilfield did the heavy lifting that built our community. You worked in the heat of the East Texas summer, breathing in the dust and chemical vapors that hovered over every job site from Gun Barrel City to Malakoff, trusting that your employer was providing a safe environment. But while you were focused on providing for your family in Henderson County, many of the corporations you worked for were focused on protecting their bottom line—even if it meant hiding the truth about asbestos fibers, benzene vapors, and toxic refinery byproducts.

If you or a loved one has been diagnosed with mesothelioma, acute myeloid leukemia (AML), or have suffered a crushing injury on an East Texas pipeline or oil rig, you are likely processing a profound sense of betrayal. The discovery that your illness was not “bad luck” but a direct result of corporate negligence often comes decades after the initial exposure. In Henderson County, we see workers who were exposed in the 1970s and 1980s only now receiving life-altering diagnoses. At Attorney 911, we believe that those who chose profits over people must be held accountable.

Ralph Manginello and our litigation team have spent over 27 years standing on the front lines against multi-billion-dollar corporations. Ralph’s experience in the BP Texas City Refinery explosion litigation—a case that ultimately totaled over $2.1 billion—proves that our firm does not back down from the largest defendants in the world. We don’t just “handle” cases; we dismantle corporate defenses. With federal court admission in the Southern District of Texas and a deep understanding of the local East Texas industrial landscape, Ralph brings a “BEAST” mentality to the courtroom that has earned the trust of over 270 verified Google reviewers.

Crucially, we offer an advantage that few other firms in Texas can claim. Our team includes Lupe Peña, an associate attorney and former insurance defense insider who spent years inside the very machine that fights against injured workers. Lupe knows the exact playbook corporate insurers use to delay, deny, and devalue toxic exposure claims. He has switched sides to ensure that the people of Henderson County have access to the same high-level tactical intelligence that once protected the corporations. That inside perspective is the nuclear differentiator in your case—we don’t just guess what the other side is thinking; we already know.

Whether your exposure happened at a local light manufacturing plant in Athens, a pipeline project near Lake Palestine, or a shipyard in the Gulf Coast that you traveled to for work, we provide a relentless, multi-front legal attack designed to maximize your recovery. You are not just another case number to us; you are family. Call 1-888-ATTY-911 for a free, confidential case evaluation. We work on a contingency fee basis, meaning you pay nothing upfront, and we advance all case costs. If we don’t win your case, you owe us nothing.

The Science of Mesothelioma: How Asbestos Destroys the Mesothelium

Mesothelioma is not like other cancers. It is a signature disease, meaning it has one primary cause: the inhalation or ingestion of asbestos fibers. In Henderson County, we see these cases frequently among retirees who worked in power generation, commercial construction, and heavy manufacturing. To understand your rights, you must first understand the biological mechanism that turned a workplace material into a terminal diagnosis.

Asbestos is not a single mineral; it is a group of silicate minerals that form thin, needle-like fibers. When these fibers are disturbed—such as when an insulator at the Trinidad power plant cut through old pipe lagging or an electrician pulled wire through asbestos-cement conduit—they become aerosolized. Because the fibers are microscopic, they are invisible to the naked eye. You may have breathed them in for years without ever realizing the air was contaminated.

The primary mechanism of injury is known as “frustrated phagocytosis.” When you inhale asbestos fibers, they migrate to the pleura, the thin membrane that lines your lungs. Your body’s immune system recognizes these fibers as foreign invaders and sends macrophages—specialized white blood cells—to engulf and destroy them. However, because asbestos fibers are rigid and biopersistent, they are too long for the macrophages to encapsulate. The macrophages die in the attempt, releasing a cascade of inflammatory cytokines (TNF-α, IL-1β) and reactive oxygen species (ROS).

This chronic inflammatory cycle continues for decades because the asbestos fibers never dissolve and can never be expelled. Over a latency period of 20 to 50 years, this constant irritation causes cumulative DNA damage to the mesothelial cells. Specifically, the fibers interfere with cell division (mitosis), leading to chromosomal translocations and the inactivation of tumor suppressor genes like BAP1 and p16. When these “brakes” on cell growth are removed, malignant cells begin to multiply uncontrollably, forming the tumors that define mesothelioma.

There is no “safe” level of asbestos exposure. The Occupational Safety and Health Administration (OSHA) currently sets a permissible exposure limit (PEL) of 0.1 fibers per cubic centimeter (f/cc) as an 8-hour time-weighted average (29 CFR 1910.1001). However, scientific consensus from the International Agency for Research on Cancer (IARC) confirms that even brief, high-intensity exposures can trigger the disease decades later. https://www.osha.gov/asbestos

In Henderson County, the diagnosis often comes in the form of pleural mesothelioma (affecting the lung lining) or peritoneal mesothelioma (affecting the abdominal cavity). Because the symptoms—shortness of breath, persistent dry cough, chest pain, and unexplained weight loss—mimic common conditions like pneumonia or COPD, many East Texas workers are initially misdiagnosed. If you have these symptoms and a history of working around insulation, gaskets, or brake products, it is critical that you seek evaluation from a specialist at a center like MD Anderson Cancer Center in Houston or UT Southwestern in Dallas.

The Dual-Pathway Compensation Strategy for Asbestos Victims

One of the most common mistakes local firms make is assuming that a mesothelioma case is either a lawsuit OR a trust fund claim. At Attorney 911, we know that for the majority of Henderson County families, it is BOTH. We pursue a parallel litigation strategy that targets every possible dollar the law allows.

Pathway 1: Asbestos Bankruptcy Trust Funds

When many of the world’s largest asbestos manufacturers—like Johns-Manville, Owens Corning, and W.R. Grace—faced thousands of lawsuits, they utilized the Chapter 11 bankruptcy process to shield themselves. As a condition of these bankruptcies, courts required the creation of personal injury trusts to pay future claimants. Currently, there are over 60 active trusts holding approximately $30 billion in assets.

These trusts do not require you to go to trial. Instead, they require specific medical and occupational proof. We specialize in reconstructing thirty and forty-year-old work histories to identify exactly which products you were exposed to. If you handled Kaylo insulation, John Crane gaskets, or Unibestos block, you may be eligible to file with multiple separate trusts simultaneously. These payments can range from tens of thousands to hundreds of thousands of dollars per trust, depending on the current payment percentage and the severity of your diagnosis.

Pathway 2: Civil Litigation Against Solvent Defendants

Many companies involved in the asbestos trade never filed for bankruptcy. If your exposure involved a premises owner (like a refinery operator that failed to clear asbestos during a turnaround) or a manufacturer that is still in business (like certain gasket or valve companies), we file a direct personal injury or wrongful death lawsuit. Unlike trust fund claims, which pay a fixed percentage, civil lawsuits allow us to pursue the full value of your economic and non-economic damages, including pain and suffering, mental anguish, and loss of consortium.

In December 2025, a jury in Baltimore awarded $1.5 billion in a single mesothelioma case against Johnson & Johnson regarding asbestos-contaminated talc. While every case is unique and past results do not guarantee future outcomes, this verdict illustrates the significant liability corporations face when they knowingly hide the dangers of their products. Attorney Ralph Manginello is a trial-ready “beast” who prepares every case as if it is going to a jury, ensuring we have maximum leverage during settlement negotiations.

Call 1-888-ATTY-911 to begin your work history reconstruction. Your immigration status does not affect your right to file a claim, and with Lupe Peña’s bilingual capability, we ensure no information is lost in translation. Hablamos Español.

Benzene and Chemical Exposure in the East Texas Oilfield

While asbestos is a solid fiber, benzene is a liquid chemical that creates even more insidious hazards for Henderson County workers. Benzene is a natural component of crude oil and a fundamental building block in the petrochemical industry. If you worked in oil and gas production, petroleum transport, or at a local manufacturing site that used industrial solvents, you were likely breathing in benzene vapors every day.

The medical science regarding benzene is devastatingly clear. Benzene is a potent hematotoxin and a known Group 1 human carcinogen. When you inhale benzene (C₆H₆), it is absorbed through the lungs and enters the bloodstream. From there, it travels to the liver, where it is metabolized by the enzyme CYP2E1 into benzene oxide and subsequently into muconaldehyde and hydroquinone.

These toxic metabolites concentrate in your bone marrow—the factory where your body produces blood cells. There, they attack hematopoietic stem cells, causing specific chromosomal translocations (such as t(8;21) or inv(16)) that disrupt normal cell development. This process can lead to:

• Acute Myeloid Leukemia (AML): A fast-growing cancer of the blood and bone marrow.
• Myelodysplastic Syndrome (MDS): Often called “pre-leukemia,” where the bone marrow fails to produce enough healthy blood cells.
• Aplastic Anemia: A condition where the body stops producing enough new blood cells.

For workers in Henderson County, benzene exposure often occurred during routine tasks that were once considered “safe.” Tank cleaning, pipe maintenance, and the use of “mineral spirits” or “parts wash” solvents often involved benzene concentrations far exceeding the OSHA PEL of 1 ppm (29 CFR 1910.1028). https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1028

In 2024, a Pennsylvania jury awarded $725 million against ExxonMobil to a former mechanic who developed AML after years of benzene exposure. This verdict sent a shockwave through the industry, proving that juries are losing patience with corporations that have known about benzene’s leukemia-link since the 1940s but failed to protect their workforce.

If you have been diagnosed with AML or MDS and have a history of working in the East Texas oilfield or industrial sector, Attorney 911 can help you identify the responsible parties. Lupe Peña’s background in insurance defense is particularly valuable here, as benzene cases often involve complex “causation” arguments where defendants try to blame your illness on smoking or genetics. We know how to shut those arguments down with hard science and expert testimony.

Dangerous Industry Accidents: Oilfield, Pipeline, and Construction Rights

Henderson County rests at the heart of East Texas, where the economy is driven by high-stakes, high-danger industries. Our workers are on the front lines of pipeline construction, heavy equipment operation, and oilfield services. When safety protocols are ignored to meet a production deadline, the results are often catastrophic.

Oilfield Blowouts and Well Control Events

The East Texas Oilfield remains one of the most active in the state. Working on a drilling rig or a frac spread involves managing extreme pressures. A blowout is not just an equipment failure; it is usually the result of multiple human errors, including inadequate mud weight monitoring, failing to maintain the blowout preventer (BOP), or ignoring warning signs of a “kick.”

If you were injured in a well-site explosion or fire, you may have rights beyond workers’ compensation. Texas uniquely allows for “non-subscriber” claims if your employer opted out of the workers’ comp system. Furthermore, most oilfields involve a “web” of contractors. If a third-party company’s negligence caused the accident, you could be entitled to full tort damages, which are not capped like workers’ comp benefits.

Pipeline and Trench Collapse

Pipeline projects near Athens and Malakoff require the excavation of deep trenches. Soil is deceptively heavy—one cubic yard of East Texas earth weighs approximately 3,000 pounds. OSHA standard 29 CFR 1926 Subpart P requires that any trench five feet or deeper must have a protective system (shoring, shielding, or sloping). https://www.osha.gov/trenching-excavation

When an employer fails to provide a trench box or fails to have a “competent person” inspect the site, they are not just being “careless”—they are breaking federal law. A trench collapse is a survivable event only if rescue happens within minutes. The pressure of the soil on a worker’s chest prevents the lungs from expanding, leading to rapid asphyxiation and crush syndrome (rhabdomyolysis), which can cause permanent kidney failure.

Industrial Explosions and the BP Texas City Legacy

Ralph Manginello’s experience in the BP Texas City litigation gives him a unique perspective on industrial disasters. We understand “Process Safety Management” (PSM) and how the violation of 29 CFR 1910.119 leads to tragedy. Whether it was a pressurized line rupture at a local chemical plant or a steam explosion at a power facility, we look for the “failure to warn” and “mechanical integrity” violations that lead to these events.

In 2023, a Harris County jury awarded $28.5 million to five workers injured in the ExxonMobil Baytown explosion. The cause was a buildup of “popcorn polymer” that the company had known was a hazard for decades. This is the level of corporate knowledge we investigate for our Henderson County clients.

Call 1-888-ATTY-911 immediately if you have been injured on a job site. Evidence like daily logs, GoPro footage, and OSHA reports can be destroyed if not preserved early. We move fast to protect your rights.

The Insider Advantage: Breaking the Corporate Defense Playbook

Why does Lupe Peña’s former career as an insurance defense attorney matter to your case in Henderson County? Because we know the three “D”s of corporate defense: Delay, Deny, and Devalue.

When a multi-billion-dollar corporation is sued for toxic exposure, they don’t just roll over. They hire defense firms that specialize in “scorched-earth” litigation. Here is how they try to stop you, and how we counter them:

1. The “Identification” Defense: In asbestos cases, they will argue you were exposed to so many products that you can’t prove their product was the one that caused the mesothelioma.

• Our Counter: We apply the “substantial factor” test. We don’t have to prove their fiber was the only one—we prove it was a significant contributor to the total dose that caused your disease.

2. The “Medical Records” Raid: They will ask for your medical records from the last 50 years, searching for any mention of smoking, obesity, or “alternative causes” to blame for your cancer.

• Our Counter: Lupe spent years reviewing these records for the other side. We know how to limit the scope of discovery and ensure your personal life isn’t put on trial to excuse their negligence.

3. The “Statute of Limitations” Trap: They will claim you waited too long to file, arguing the clock should have started years ago.

• Our Counter: We utilize the Texas Discovery Rule. In latent disease cases, the clock doesn’t start when you were exposed; it starts when you discovered your injury and its connection to the workplace. We establish the timeline to protect your right to sue.

4. The “Terminal Delay” Strategy: Tragically, in mesothelioma cases, the defense knows the median survival is often short. They will file endless motions to delay the trial in the hopes the plaintiff passes away, reducing the emotional impact on a potential jury.

• Our Counter: We file for Expedited Discovery and Trial Preference. In Texas, terminal patients can often have their cases fast-tracked. We take “preservation depositions” immediately to ensure your story is told, no matter what.

As Ralph Manginello explains on the Attorney 911 podcast, “What Is a Million-Dollar Case?” (Ep. 11), a case only reaches its true value when the defendant knows you are ready to take it to trial. https://share.transistor.fm/s/d690a218

The Multi-Exposure Bridge: When Harms Overlap

Many Henderson County workers don’t just have one exposure; they have a “stack” of claims. Consider a career pipeline welder:

• Axis 1 (Substance): You inhaled welding fumes containing manganese (linked to manganism/Parkinsonism) and hexavalent chromium (linked to lung cancer).
• Axis 2 (Industry): You faced acute injury risks from pipeline trench collapses or high-voltage electrocution.
• The Anchor: You likely handled legacy asbestos blankets or were exposed to asbestos insulation on old refinery connections while performing hot work.

Most law firms might only look at the workers’ comp claim for a back injury. Attorney 911 looks at the ENTIRE person. We investigate whether you qualify for asbestos trust funds, a benzene PI claim, AND a FELA claim (if exposed on railroad projects). Combining these pathways doesn’t just “add” to your settlement; it can multiply it tens of times over.

Secondary Exposure: Protecting the Families of Athens and Gun Barrel City

In East Texas, the danger didn’t always stay at the plant. In the 1960s and 70s, it was common for workers to come home covered in the “dust of the day.” This white, chalky dust was often raw asbestos or silica fibers. When a worker’s wife laundered his work clothes, she shook out those fibers, inhaling them in the concentrated air of the laundry room. When children hugged their fathers coming home from the brick plant or the refinery, they were exposed to fibers trapped in his hair and skin.

This is known as Secondary (Take-Home) Exposure. We represent spouses and adult children in Henderson County who were never industrial workers themselves but have now been diagnosed with mesothelioma or lung disease. The law recognizes that an employer’s duty to provide a safe environment extended to the family members they knew would be impacted by take-home toxins.

As Leonor, our lead case manager, explains in her episode “Facts to Remember After an Accident” (Ep. 1), documenting these historical domestic details is just as important as the workplace logs. https://share.transistor.fm/s/a85410a7

Corporate Accountability: The Documents They Tried to Burn

The anger our clients feel is justified by the evidence. This was not a scientific “accident.” The history of toxic exposure in America is a history of documented conspiracy.

• The Sumner Simpson Letters (1935): The president of Raybestos-Manhattan wrote to the attorney for Johns-Manville, agreeing that “the less said about asbestos, the better off we are.” They chose to suppress medical research for decades while millions of workers were exposed.
• The Monsanto Papers: Internal emails revealed in Roundup litigation showed that Monsanto employees ghostwrote studies that claimed glyphosate was safe, then paid academics to put their names on them to trick the EPA.
• The 3M PFAS Memos: Internal documents dating to the 1970s show 3M knew “forever chemicals” were accumulating in human blood but hid that data from regulators for thirty years.

In Henderson County, we hold these companies to account based on their own internal records. When you hire Ralph Manginello, you are hiring a firm that uses these “smoking gun” documents to prove the GROSS NEGLIGENCE required for punitive damages—awards designed specifically to punish the defendant and prevent it from happening again.

Frequently Asked Questions: Toxic Exposure in Henderson County

I was exposed 40 years ago. Can I still file a claim?

Yes. Under the Texas Discovery Rule, the two-year statute of limitations typically doesn’t begin until you receive a diagnosis and realize it was caused by workplace exposure. For diseases like mesothelioma with a long latency period, this is the standard. Don’t assume it’s too late; call 1-888-ATTY-911 to check your specific deadlines.

Does filing a trust fund claim affect my social security or VA benefits?

Generally, no. Asbestos trust fund payments and civil lawsuit settlements are separate from your government benefits. If you are a veteran, you may qualify for VA disability AND trust fund compensation. We help coordinate these to ensure you receive everything you’re entitled to.

My employer is bankrupt. Is there still money available?

Yes. This is why the bankruptcy trusts exist. Even if the company that exposed you in the 1970s is long gone, the money they were required to set aside in the trust is still there to compensate victims. We file claims across all 60+ active trusts to maximize your recovery.

What if I don’t know exactly which product I was exposed to?

That’s why you hire us. We use product ID databases, union local dispatch records, and co-worker affidavits to reconstruct your job site. We know which manufacturers’ insulation was used at the Trinidad plant and which gaskets were standard in East Texas oilfield service. You tell us where you worked; we identify the toxins.

I am undocumented. Can the company report me to ICE if I sue?

Federal law protects all workers in the U.S. regardless of their immigration status. It is illegal for an employer to use immigration status as a tool of retaliation in a personal injury or toxic exposure case. We advocate for our clients’ rights and their safety. Lupe Peña can discuss your case in confidence. Hablamos Español.

How much is my case worth?

Every case depends on the severity of the injury and the strength of the exposure proof. However, industry averages show mesothelioma settlements often range from $1 million to $1.4 million, with verdicts reaching much higher. Benzene and industrial accident cases also regularly reach seven and eight-figure values. We fight for the maximum recovery in every case.

Why Henderson County Chooses The Manginello Law Firm

We are not a “settlement mill” that signs up thousands of people only to never return their calls. As Chad Harris wrote in his 5-star Google review, “Unlike some law firms where you are dealing with an answering service… Atty. Manginello and I had DIRECT COMMUNICATION. You are not a pest to them… You are FAMILY.”

When you call 1-888-ATTY-911, you are calling a firm rooted in Texas values. Ralph Manginello grew up in Houston’s Memorial area and has spent his life in these courts. We know the roads you drive—Highway 175, State Highway 31—and we know the facilities where you worked. We leverage this local knowledge with a national-level litigation engine to deliver the results you deserve.

The corporations that poisoned you have a team of lawyers whose only job is to ensure you get nothing. You need a team that knows their tactics from the inside. With Ralph Manginello’s 27+ years of trial experience and Lupe Peña’s defense-side insider intelligence, we are the most dangerous firm a corporate defendant can face.

Your fight for justice doesn’t have to be a lonely one. We carry the legal burden so you can focus on your health and your family. We offer medical assistance through letters of protection (LOPs), ensuring you get to the right doctors even if you are currently uninsured. As Ralph explains in his video, “Do I Have to See My Lawyer’s Doctor?” (YouTube), we prioritize your health outcomes alongside your legal outcomes. https://www.youtube.com/watch?v=xfT0hr69ZWk

Evidence Preservation: Why the First 30 Days Matter

In Henderson County, evidence of your exposure is disappearing every day. Former shop foremen are passing away. Blueprints of old facilities are being shredded during corporate acquisitions. Sites like the old Athens brickworks or decommissioned power units are being demolished, taking the physical proof of asbestos with them.

When we are retained, we immediately send “Spoliation Letters” to every identified defendant. These are formal legal notices that require the company to preserve all industrial hygiene reports, OSHA 300 logs, and material safety data sheets (MSDS). If they destroy evidence after receiving our notice, we can ask the court for “adverse inference” instructions—essentially telling the jury that the company destroyed proof because it showed they were guilty.

Waiting is a strategy the corporations want you to follow. Every month of delay is another opportunity for a witness to disappear or a trust fund to lower its payment percentage. The Manville Trust, for example, has seen its payment percentage drop significantly over time as its assets are depleted. Securing your place in the queue NOW is critical for your financial future.

Conclusion: Take Action for Your Family’s Future

You spent your life building East Texas. You showed up for the double shifts, the refinery turnarounds, and the rig moves, trusting that if you did your part, the company would do theirs. They didn’t. They let you breathe in death while they breathed in profit.

Now, you have the right to look them in the eye and demand accountability. You have the right to ensure your spouse is taken care of, your medical bills are paid, and your family’s future is secure. This is your “911” emergency—and we are the firm built to answer it.

Attorney Ralph Manginello and Lupe Peña are ready to take your call. We serve Henderson County and the entire state of Texas from our offices in Houston, Austin, and Beaumont. We will travel to you, meet with you virtually, or host you in our office—whatever it takes to get your case moving.

As Stephanie Hernandez shared in her 5-star review: “When I felt I had no hope or direction… they really made me feel like I mattered throughout the entire process.” You matter to us. Your sacrifice matters. And the law is on your side.

Call 1-888-ATTY-911.
Free Consultation.
No Fee Unless We Win.
Principal Office: Houston, Texas.

Attorney 911: Because the companies that knew shouldn’t get away with it.

Disclaimer: Past results do not guarantee future outcomes. This information is for educational purposes and does not constitute legal advice. Every case is unique. Contact us for a free consultation about your specific situation. Statistics regarding trust fund payments and verdict ranges are based on industry data and public records.

Authoritative Reference Library for E-E-A-T (Appendix C Deployment)

1. OSHA Asbestos Standard for General Industry (29 CFR 1910.1001) – https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1001
2. NCI Asbestos Exposure and Cancer Risk Fact Sheet – https://www.cancer.gov/about-cancer/causes-prevention/risk/substances/asbestos/asbestos-fact-sheet
3. IARC Monograph 120: Benzene Carcinogenicity – https://publications.iarc.who.int/576
4. ATSDR Toxicological Profile for Benzene – https://www.atsdr.cdc.gov/toxprofiles/tp3.pdf
5. OSHA Process Safety Management (29 CFR 1910.119) – https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.119
6. CDC/NIOSH Silicosis Resources – https://www.cdc.gov/niosh/silica/about/
7. EPA PFAS Strategic Roadmap – https://www.epa.gov/pfas/pfas-strategic-roadmap-epas-commitments-action-2021-2024
8. National Cancer Institute: Mesothelioma Staging – https://www.cancer.gov/types/mesothelioma
9. US Department of Labor: FELA Claims – https://www.dol.gov/agencies/owcp/dcmwc
10. American Lung Association: Living with Mesothelioma – https://www.lung.org
11. Texas Presumption Statute for Firefighters – Tex. Gov’t Code § 607.055
12. EPA Safe Drinking Water Act (Benzene MCL) – https://www.epa.gov/ground-water-and-drinking-water/national-primary-drinking-water-regulations
13. NIOSH B-Reader Program – https://www.cdc.gov/niosh/topics/chestradiography/breader-info.html
14. Journal of the National Cancer Institute: Hair Relaxer Study (2022) – https://academic.oup.com/jnci
15. VA Toxic Exposure Screening Information – https://www.va.gov/resources/the-pact-act-and-your-va-benefits/
16. ClinicalTrials.gov: Current Mesothelioma Trials – https://clinicaltrials.gov/search?cond=Mesothelioma
17. IARC Monograph 112: Glyphosate (Roundup) – https://publications.iarc.who.int/549
18. OSHA Excavation Standard (29 CFR 1926 Subpart P) – https://www.osha.gov/trenching-excavation