FORMAL RECOMMENDATION BY THE

NATIONAL ORGANIC STANDARDS BOARD (NOSB) 

TO THE NATIONAL ORGANIC PROGRAM (NOP) 

Date: _____6-3-06___________________

Subject: Sunset Review - 205.601 Synthetic substances allowed for use in organic crop 

production 

Chair: Kevin O’Rell 

Recommendation

The NOSB hereby recommends to the NOP the following: 

Rulemaking Action: _XXXXXX_ 

Guidance Statement: ________ 

Other: ________ 

Statement of the Recommendation (including Recount of Vote):

See attached Recommendation for Renewal of Hydrated Lime as Synthetic substances allowed 

for use in organic crop production on 205.601, category use (i) as plant disease control. 

NOSB Vote: 

Moved: Gerald Davis Second: Nancy Ostiguy 

Yes – 12 

No – 0 

Abstain – 0 

Absent – 2 

Rationale Supporting Recommendation (including consistency with OFPA and NOP):

NOSB Sunset Material Vote 

Response by the NOP:
NOSB- Crops Committee 

Hydrated Lime- Sunset Recommendation 

Final NOSB Recommendation 4/20/2006 

I. List: 205.601 Synthetic substances allowed for use in organic crop production

II. Category Use 

 (i) As plant disease control 

III. Committee Summary: The renewal of hydrated lime was deferred for two reasons. 

First, the Crops Committee thought that more information and public comment was 

needed, and second, because of concern that there was no OFPA category that 

specifically allows its use. 

Review of the Technical Evaluation Report shows that hydrated lime (calcium hydroxide, 

slaked lime, calcium hydrate, carboxide, lime water) is a synthetic produced by the slow 

addition of water to crushed or ground quicklime (calcium oxide), which is produced by 

burning various forms of limestone. The burning of limestone requires temperatures of 

1,000* F, and the addition of water to the resulting quicklime generates considerable heat 

and steam. Calcium hydroxide may also be produced as a by-product of industrial 

processes, such as the generation of acetylene from calcium carbide. More than 90% of 

the burned lime produced in the US is used for industrial chemistry, such as steel 

manufacture, metallurgy, air and waste water pollution control, cement, glass, chemical 

and paper manufacture, and as an ingredient in pesticides such as lime-sulfur and 

Bordeaux mixture. Calcium hydroxide ionizes readily in water, is slightly soluble in 

water, and reacts violently with acids. Environmental concerns include the large amounts 

of energy required in production, the amount of dust created during various stages of 

mining and processing, and that by-product sources may be contaminated with heavy 

metals. With regard to human health, calcium hydroxide can severely irritate and / or 

burn the eyes, skin, mucous membranes, lungs, nose, and throat, along with vomiting, 

diarrhea, collapse and delayed esophageal damage if ingested. Used as intended as an aid 

in foliar plant disease control, calcium hydroxide would not have a detrimental effect on 

the soil or on soil organisms. 

Most of the public comments were in favor of keeping hydrated lime on the National 

List. The manufacture of lime-sulfur, which many commentators said they could not 

farm organically without, requires the use of hydrated lime, as does the on-farm 

production of Bordeaux mixture (copper containing compound). Lime sulfur is used to 

control fungus, mites, and insects in apples, grapes, blueberries, cherries, and other tree 

and vine crops. Some commentators made the point that lime sulfur has been used for 

two hundred (200) years with no recorded loss of effectiveness (resistance). One 

commentator stated that no synthetic substances should be allowed in organic, but failed 

to show how these materials violate OFPA. In the opinion of this committee, hydrated 

lime should be considered a production aid, insofar as it is vital to the production of two 

exempted sulfur or copper containing materials in order to make these materials nonphytotoxic to plants. 
IV. Committee Recommendation: 

Recommendations based upon comments received – 205.601(i)

 

The Crops Committee recommends renewing the following material to the National List: 

(i) As plant disease control 

 (3) Hydrated lime 

Motion: Kevin Engelbert Second: Jeff Moyer 

Committee vote: 1 Yes, 2 No 

NOSB vote: 

Motion: Gerald Davis Second: Nancy Ostiguy 

Yes – 12 

No – 0 

Abstain – 0 

Absent – 0 
(2)