The Risk of Methyl Mercaptan Exposure in Chemical Plants

Many chemical plants use or produce the chemical methyl mercaptan. While chemical plants and workers are required to take steps to reduce the risks when working with or around this toxic substance, those safety measures sometimes fail—and workers are hurt or killed as a result. Methyl mercaptan poses a number of risks, but gas leaks can be especially dangerous for plant workers. When a leak develops from an accident, mistake, or lack of safety inspections, the threat is invisible, silent, deadly, and often undetectable to the workers who are in danger.   

What Is Methyl Mercaptan?

Methyl mercaptan (CH 4 S)—also known as mercaptomethane, methanethiol, methyl sulfhydrate, and thiomethyl alcohol—is a gas that is commonly used in a number of products, including use in pesticides, in plastics, and as an additive to natural gas to give it an odor. Methyl mercaptan has a strong smell that has been described as similar to “rotten cabbage.”  This toxic substance can be extremely harmful if inhaled at a high-enough concentration or if it makes contact with unprotected skin and eyes.

What Happens If I Am Exposed to Methyl Mercaptan?

The current OSHA-permissible exposure limit is 10 parts of methyl mercaptan per cubic meter of air as a ceiling concentration. Workers who are exposed to dangerous levels of the gas as the result of a leak or accident can suffer very serious injuries or even tragically lose their lives.  

The most common symptoms of exposure to the gas include:

  • Headaches
  • Dizziness
  • Staggered gait
  • Nausea
  • Vomiting
  • Pulmonary irritation and/or pulmonary edema
  • Tremors and seizures
  • Wheezing when you exhale
  • Rapid heartbeat
  • Liver and kidney damage
  • Rigidity of the arms and legs
  • Bluish discoloration of the skin and mucous membranes (cyanosis)
  • Irritation of the eyes and mucous membranes

Industry safety standards generally require that anyone working with this dangerous substance wear chemical protective clothing, gloves, a face shield, and other protective items needed to avoid skin contact.

Why Are Chemical Plant Employees at Risk for Exposure?

Workers at chemical plants that produce or use methyl mercaptan are put at risk when there is an accident or a gas leak develops. Although the gas has a strong smell, workers in chemical plants can experience “olfactory fatigue”—meaning that their sense of smell can become dulled over time to the odor of the chemical. As toxic levels of gas from a leak build, workers may be completely unaware of the danger. In a tragic example, four workers with a DuPont plant in La Porte, Texas lost their lives and one more was hospitalized after a methyl mercaptan leak developed from a faulty valve at the worksite.

While there are strict industry standards for safety and maintenance when working with methyl mercaptan, the reality is that some companies cut corners when it comes to safety. According to a report from The Texas Tribune about the most recent fatal incident, the DuPont plant in La Porte has been written up more than 20 times in the last five years by the Texas Commission on Environmental Quality for violations that include:

  • Not performing routine safety inspections
  • Failing to keep equipment in working order
  • Failing to prevent pollution leaks

How Can I Get More Information If I’ve Been Exposed to a Methyl Mercaptan Leak at a Chemical Plant?

If you have been exposed to a methyl mercaptan leak, or if you are concerned about a family member who has been exposed, prompt medical treatment should be the first step. A doctor can address the immediate symptoms of exposure, give you more information about the type of treatment you will need, and explain what to expect from your recovery.

After your medical needs have been addressed, conducting an independent investigation can help you preserve evidence that might get lost or destroyed over time and get answers to your questions about what happens next. After a leak at a chemical plant, the company and federal safety agencies, such as the U.S. Chemical Safety Board, will most likely launch their own investigations into the cause of the toxic exposure to the gas, but the results of their investigations may not be released in time for the results to be useful to you. This is why it is so important to take your own steps to get answers.  

To find out more about what to do after you've been exposed to methyl mercaptan at a chemical plant or to start an independent investigation, call our Houston team directly at 1-(877) 724-7800 or fill out the contact form on this page.


Vuk Stevan Vujasinovic
Experienced Injury Lawyer. First Generation American. Life-Long Texan. Husband. Father.