Hydrogen Sulfide

Hydrogen sulfide (H2S) is an invisible hazard that can be released and produced during industry processes, such as drilling. H2S can also develop naturally in oxygen deficient environments, such as bogs, swamps, polluted water, and manure pits.

H2S can collect in: Low-lying areas Any enclosed facility or piping that contains H2S or H2S-contaminated fluids Pits Tanks Vacuum trucks Confined spaces

At high concentrations, H2S can kill in a single breath.

Multiple agencies provide guidelines to help workers avoid H2S exposure, including the American National Standards Institute (ANSI). ANSI recently updated its Z-390 standard for Accepted Practices for Hydrogen Sulfide Safety Training Programs.

The 2006 version of the ANSI Z-390 standard was revised to address: References to obsolete technology Non-flexible presentation format Required presentation of material that wasn’t pertinent to most workers Structure of document Visitor training Refresher training Threshold limit value –time-weighted average (TLV-TWA)

The updated 2017 version of the ANSI Z-390 standard now: References updated technology Has flexible structure open to partial remote instruction States that students must be presented with relevant information to ensure their safety Has an improved structure States that visitors must receive full worker training program Requires refresher training annually with full course presentation Includes the updated American Conference of Governmental Industrial Hygienists (ACGIH) TLV-TWA

Companies must use engineering and administrative controls to protect workers from H2S exposure and provide workers with training appropriate to their potential level of exposure to H2S. https://www.osha.gov/dts/maritime/standards/guidance/shipyard_guidance.html

Some examples of what training should cover include: Wind direction awareness and routes of egress What to do in an emergency Participating in drills

Characteristics of H2S include: H2S goes by many names, including The Silent Killer, rotten egg gas, swamp gas, and sour gas. Characteristics of H2S include: Highly toxic, colorless gas Extremely flammable, may ignite at high temperatures Extremely explosive, containers of H2S may explode if exposed to fire or handled carelessly

You can only smell low concentrations of H2S You can only smell low concentrations of H2S. At high concentrations, H2S impairs and eventually wipes out your sense of smell. Do not use your nose to detect H2S.

You can be exposed to H2S through: Inhalation is your main concern. Skin contact Inhalation is your main concern.

Symptoms of H2S exposure include: Acute Toxicity Chronic Toxicity Loss of sense of smell Excitement or giddiness Eye irritation Coughing and sneezing Headaches Nausea Respiratory tract irritation Diarrhea Corneal blistering, pitting, and opacity Pulmonary edema Loss of appetite Sleep disturbances

The industry accepted exposure level for H2S is 10 ppm: Check with your company for its accepted exposure level

If the H2S concentration may exceed 10 ppm, you need to wear a personal monitor: Position the monitor as close to your mouth and nose as possible to measure air from the breathing zone If your monitor goes off, leave the area immediately

Wind conditions tell you which way H2S will spread: Check the windsock or streamer regularly and any time you are unsure which way the wind is blowing Stay on the upwind side Make sure you are not downwind of an H2S source Always move crosswind and then upwind to get away from an H2S source

ANSI and the American Petroleum Institute (API) recommend wearing one of the following respirators when you work in environments with more than 10 ppm H2S: Positive-pressure full-facepiece hoseline/airline supplied-air respirator (SAR) and carry an escape pack Positive-pressure self-contained breathing apparatus (SCBA)

H2S is a deadly hazard that can kill you in a single breath H2S is a deadly hazard that can kill you in a single breath. Know your role in your company’s H2S contingency plan and participate in drills.

Do not rely on your sense of smell to detect the presence of H2S Do not rely on your sense of smell to detect the presence of H2S. Always wear a personal monitor when working in potential H2S environments. If your monitor goes off, leave the area immediately.