“It’s mostly cells and then media. I don’t know if that counts as chemicals.” That sentence comes up on a lot of early biotech discovery calls. So does “we’re more of a software company.” Both are signals that the founder is doing real lab work but isn’t sure whether the Cal/OSHA Laboratory Standard applies.

Why “Just Cells and Media” Almost Always Includes Hazardous Chemicals

When clients describe their work as “cells and media,” they mean the high-level science: growing mammalian cells, applying growth factors, running assays. What they’re not describing is the supporting chemistry on the bench next to the incubator. That’s where the CHP requirement comes from.

A typical biotech bench includes some combination of the following, most of which are hazardous chemicals under Cal/OSHA’s definition:

• Fixatives: formaldehyde, paraformaldehyde, glutaraldehyde. Sensitizers and suspected carcinogens with low exposure limits.
• Stains and dyes: DAPI, propidium iodide, crystal violet, ethidium bromide. Several are classified as toxic or suspected mutagens.
• Organic solvents: methanol, ethanol, isopropanol, DMSO, acetone, xylene, chloroform. Flammable, with varying health-hazard classifications.
• Reagent components: sodium azide preservative, beta-mercaptoethanol, acrylamide solutions, phenol-containing extraction kits.
• Disinfectants in working concentrations: bleach (sodium hypochlorite) and concentrated ethanol.
• Compressed gases: CO2, liquid nitrogen, O2, N2 cylinders. Even non-toxic gases under pressure count as hazardous chemicals because of the physical hazard.

Most are present from day one. A handful at small volumes is enough to put the lab under the Laboratory Standard. The CHP is not gated by chemical quantity the way a Hazardous Materials Business Plan is. It is gated by whether the activity meets Cal/OSHA’s definition of a laboratory and uses hazardous chemicals at all.

A narrow exception: chemicals impregnated into test strips (pH strips, dipstick assays, lateral-flow devices) are not considered hazardous chemicals under Section 5191. Compressed cylinder gases, even non-toxic ones, are. The line moves chemical by chemical, so a materials-list review is the fastest way to confirm what triggers what.

“Does Your Lab Trigger a CHP?” Decision Checklist

Run this against your operation. If the first three apply and any item in the fourth applies, the CHP requirement is almost certainly active.

A “we only use cells and media” operation almost always checks all four, because cells and media don’t grow in isolation. The supporting chemistry comes with them.

“We’re a Software Company” Doesn’t Change the Answer

A common framing on early calls is “we’re really more of a software company that happens to be running some lab experiments.” Tech-origin founders pivoting into life sciences are a category by themselves: a small lab in a corner of a larger office, often staffed by a single scientist plus contractors.

The regulation does not care what your company’s primary business is. It cares whether you operate a laboratory and use hazardous chemicals. A three-person stem-cell startup with one bench and a fume hood is subject to the same Laboratory Standard as a 30-person diagnostics company. The plan gets right-sized to the actual chemical inventory and headcount.

Two practical points come up with this archetype:

• Employee count affects scope, not applicability. Crossing the 10-employee threshold expands some Cal/OSHA program requirements, but the CHP itself is not exempted below 10. A three-scientist pre-revenue lab still needs a written plan, a designated Chemical Hygiene Officer, training, and SOPs. The plan can be sized for that team and built to scale.
• Quality and EHS requirements are different. Tech-founder labs conflate them. HEPA filtration, ISO-classified clean rooms, and laminar flow hoods are usually quality requirements for cell culture integrity, driven by your science. Chemical fume hood ventilation, eye wash stations, PPE, and the CHP are EHS requirements for employee protection, driven by Cal/OSHA. You may need both, from different regulators.

What Happens After “Yes, We Need One”

The Cal/OSHA Laboratory Standard requires a written CHP with elements covering chemical procurement, storage, environmental monitoring, PPE, training, spill response, and waste disposal. A generic internet template will not survive a Cal/OSHA inspection because it doesn’t reflect your chemicals, your fume hood configuration, your CHO, or your SOPs (standard operating procedures). For what a real CHP includes, see What Is a Chemical Hygiene Plan? (and Why a Template Isn’t Enough).

If you’re standing up a lab from scratch, the CHP usually sits inside a broader package alongside an IIPP (Injury and Illness Prevention Program), a HazCom program, an Emergency Action Plan, and (above chemical-quantity thresholds) a Hazardous Materials Business Plan filed through CERS, the state’s online environmental reporting portal. The BSL-2 lab requirements checklist walks through that full set.

The CHP stays on-site at your facility. It is not submitted to your local CUPA (which may be a county environmental health department, fire department, or another local agency depending on jurisdiction) or to any agency. It must be available on request, current, and reflective of what’s happening at the bench.