Contraflowlane

Any space using HF should be clearly labeled throughout the process. The 'Hydrofluoric Acid In Use' sign should not be removed until work has been completed and the area has been cleaned. Specialty first aid equipment, calcium gluconate (Calgonate®) must be kept on hand and easily accessible. To handle a small spill (<20 mL), calcium carbonate or a commercial, HF specific, spill kit should be kept near HF worksite.

Inhaling HF vapors can seriously damage the lungs. Delayed reactions up to and including fatal pulmonary edema (flooding of the lungs with body fluids) may not be apparent for hours after the initial exposure. Airborne concentrations of 10 to 15 ppm will irritate the eyes, skin, and respiratory tract. Thirty ppm is considered immediately dangerous to life and health and may have irreversible health effects. At airborne concentrations above 50 ppm, even brief exposure may be fatal. All operations involving HF must be conducted in an exhausting hood.

NACTO bus lanes

Skin exposure to concentrated HF (49% or greater) immediately results in serious and painful destruction of tissue. One of HF’s most insidious properties is that skin contact at lower concentrations may not produce pain or burning sensations until hours after the exposure. Because of the ability of HF to produce severe delayed tissue damage without producing pain, all skin, eye, or tissue contact with HF should receive immediate first aid and medical evaluation, even if the injury appears minor or no pain is felt.

Due to longstanding issues of congestion, there have been several initiatives (focused on roadway widenings and HOV lanes) to improve corridor conditions on US 101 over the past few decades. However, because of the corridor’s constrained right-of-way and the high costs to expand the roadway, regional agencies are examining alternate, faster strategies to improve travel through the corridor, including consideration of ramp metering and part-time transit lanes.

Curbsidelane

The hazard assessment tool does not expressly cover hydrofluoric acid use, only the general use of corrosives. It is UCSC policy to add a custom hazard to the assessment of any lab conducting work with HF. The following information should be added to the "Custom Laboratory Activities" section of LHAT. Note that lab members are still required to take the in person training for HF use.

The following is an estimated milestone timeline for the development of the US 101 Part-Time Transit Lane Feasibility Study:

Although part-time transit lanes are a relatively new transit tool in California, other US cities have implemented this strategy with much success. When buses can access part-time transit lanes, it results in several benefits:

BATlane

US 101 forms the backbone of Marin County’s transportation network. The north-south corridor is critical to both regional and local travel, providing connections to neighboring San Francisco, Sonoma County, and Contra Costa County. Two transit agencies serve the US 101 corridor in Marin County: Marin Transit offers local service internal to Marin County and Golden Gate Transit provides connections between and within Sonoma, Marin, and San Francisco Counties.

Wearing and properly removing Personnel Protective Equipment (PPE) is essential for safely handling HF. Before using PPE always check the condition and functionality (e.g., check gloves for pinholes or for any discolored or brittle sections; chemical splash goggles and face shield for cracks or dirt, coat for holes or tears).

Let us know your thoughts and ideas about the future Part-Time Transit Lane service. Please send comments to [email protected]

TransitGuidelines

TransitWay

The Transportation Authority of Marin (TAM) conducted a preliminary study to determine the suitability, benefits, costs, and other considerations to implement part-time transit lane operations along the US 101 corridor from Atherton Avenue/San Marin Drive in Novato to Mission Avenue in San Rafael. This span of highway is approximately 11 miles and features 12 interchanges and local connecting roads, most of which have bus stops.

Currently, transit travel times in the US 101 corridor degrade substantially in the southbound morning commute, and transit service reliability suffers. Southbound morning congestion is forecasted to continue to increase in coming years. In addition, the reverse commute north towards Sonoma County is expected to grow with increasing traffic volumes.

When handling concentrated HF a vinyl, or other chemical resistant (Tychem), lab apron should be worn over the protection listed.

Transitarchitecture

Hydrofluoric acid, hydrogen fluoride in water, has many uses in research laboratories. HF can be used to etch silicon for semiconductor work and can also be used to dissolve rock samples. The use of hydrofluoric acid (HF), at any concentration, requires some unique laboratory preparation and safety precautions. All corrosive material should be handled with care, but HF's high corrosive nature and ability to permeate tissue make it a particular concern. If you intend to use HF in your research please review the information in this section and follow the UC-required SOP as approved by your PI. If there is not an existing HF SOP for your lab that covers your process, please contact EH&S prior to use for assistance in developing a process-specific SOP which is reviewed and approved by your PI.

Transitstreets

The US 101 Part-Time Transit Lane Feasibility Study will assess the feasibility of part-time transit lanes on the US 101 corridor in central and northern Marin County. Converting highway shoulder lanes to part-time transit lanes to bypass congestion improves transit reliability, making transit a more attractive travel choice for commuters. Prior to COVID-related service changes, there were over 350 daily bus trips and several thousand daily riders on this stretch of US 101.

This project is funded by the Sustainable Communities (SB-1) Grant awarded to TAM by the California Department of Transportation (Caltrans).

As the US 101 Part-Time Transit Lane Feasibility Study progresses forward, updates will be provided here when there are opportunities for public involvement.

Skin and Body Protection: An appropriately-sized lab coat must be worn and buttoned to its full length. Laboratory coat sleeves must be of sufficient length to prevent skin exposure while wearing gloves. Full length pants and closed-toe shoes must be worn at all times by the individual conducting the work, and by all others within the laboratory. No portion of the body should be exposed. Coat material should be cotton, polyester or a blend of the two. Nomex coats should not be worn as the acid will penetrate the material.

Glove selection: Concentrated HF - wear heavy (22 mil) nitrile or neoprene gloves when working with concentrated (49%) HF. These gloves should have a long cuff, coming up the forearm. Check chemical compatibility of gloves for other reagents used while handling HF. Dilute HF - disposable gloves (5 mil) can be used but should be doubled (one size larger over the normal size) when using dilute (<20%) HF. Outer glove can be removed and replaced if incidental contact is detected. After handling HF, remove gloves and wash hands with soap and water.

With part-time transit lanes, buses are authorized to use the outside freeway shoulder to bypass congestion. Use of the part-time transit lane is often limited to peak periods of the day when there is recurring congestion.  Buses would only use the part-time transit lane when travel speeds on the freeway drop below 35 miles per hour and the maximum speed for the buses would be 35 miles per hour. If the part-time transit lane is in use by CHP or closed due to construction or an incident, then buses would use the main freeway lanes. These measures ensure that part-time transit lanes can be implemented safely while also benefitting transit riders when congestion and ridership are the highest.

Hydrofluoric acid is corrosive and readily destroys tissue and bone. HF readily penetrates human skin, allowing it to destroy soft tissues underneath and to decalcify bone (hypocalcemea). HF is moderately corrosive to metals and will dissolve glass – hydrofluoric acid must not be stored in glass bottles.

Eye Protection: Work with HF should be conducted with chemical splash goggles not safety glasses; safety glasses do not provide sufficient protection. Use of a full-face shield is recommended, especially when handling high concentrations or volumes.